3D Head Shape Feature Analysis of Zika-Infected Children.

Congenital Zika syndrome (CZS) has been identified a constellation of congenital anomalies caused by Zika Virus (ZKV) infection during pregnancy. The infection with ZKV could lead to microcephaly of the fetus due to a severe decrease in brain volume and reduced brain growth. The preliminary screening of CZS is based on measuring head circumference; the diagnosis is made if this measurement is below two standard deviations below the mean. The analyses of the 3D head features of infected infants are limited. This study analyzed 3D head images of 35 ZKV-positive cases with an average age of 16.8 ± 2 months and 35 controls with an average age of 14.4 ± 5 months. This study focused on identifying potential diagnostic characteristics of CZS. The 3D head images were captured using a 3D imaging system. The averaged images of the two groups were aligned to illustrate the size and shape differences. There were significant differences in centroid size, head circumference (HC), head height (HH), and chin height (CH) between the two groups. We also identified significant differences in the indices of chin height/total facial height (CH/TFH) and head height/head circumference ratio (HH/HC) between the CZS and control cases. An HH/HC of 0.49 showed a sensitivity of 0.86 and a specificity of 0.74 in diagnosing CZS, which is more sensitive than the routinely used HC measurement. The index of HH/HC has potential to be used as the gold standard for the early screening for the detection of CZS cases.

Computed Tomography Findings of Patients Presenting With Headache: 4-Year Retrospective Two-Center Study in Central and Western Regions of Ghana.

Objectives: The radiographic assessment of the head is a crucial part of headache care. A computed tomography (CT) scan enables a more detailed analysis of the condition and more focused care. This study examined head CT scans to determine what kinds of anomalies were present in patients with headaches as their primary complaint. Methods: We evaluated 4 years' worth of CT scan data from head exams conducted at two diagnostic facilities in Ghana's western and central regions. We examined data on 477 patients with a headache as their primary complaint between January 2017 and December 2020. We employed chi-square and Fisher's exact tests (where applicable) to compare head CT diagnoses between age groups, gender, headache subtypes, and brain lesion subgroups. Results: There were 53.5% (n = 255) females and 46.5% (n = 222) males in the study. The average age of patients was 38.67 ± 17.23 years, with an annual rate of abnormal CT diagnoses ranging from 35.9% in 2017 to 45.4% in 2022. Abnormal head CT diagnoses are strongly correlated with age groups and patient gender (p = 0.011 and p = 0.009, respectively). Of the 202 patients, 15.3% and 24.3% were classified as intracranial lesions and extracranial lesions, respectively. Maxillary sinusitis affected nearly 60% of the patients, while tumors and hemorrhages affected 25.2% and 11.9%, respectively. Conclusions: A CT scan of the head is essential to detect abnormalities in nearly 50% of patients suffering from various degrees of headache. Sinusitis, brain tumors, and hemorrhage were common lesions detected. It is crucial to create local standard operating procedures to promote better utilization of this type of imaging service, particularly among patients who have been diagnosed with headaches.

Nontraumatic Pediatric Head and Neck Emergencies: Resource for On-Call Radiologists.

The vast array of acute nontraumatic diseases encountered in the head and neck of pediatric patients can be intimidating for radiologists in training in a fast-paced emergency setting. Although there is some overlap of pediatric and adult diseases, congenital lesions and developmental variants are much more common in the pediatric population. Furthermore, the relative incidences of numerous infections and neoplasms differ between pediatric and adult populations. Young patients and/or those with developmental delays may have clinical histories that are difficult to elicit or nonspecific presentations, underscoring the importance of imaging in facilitating accurate and timely diagnoses. It is essential that radiologists caring for children be well versed in pediatric nontraumatic head and neck emergency imaging. The authors provide an on-call resource for radiology trainees, organized by anatomic location and highlighting key points, pearls, pitfalls, and mimics of many acute nontraumatic diseases in the pediatric head and neck. ©RSNA, 2024 Supplemental material is available for this article.

Evaluating the Usability and Quality of a Clinical Mobile App for Assisting Physicians in Head Computed Tomography Scan Ordering: Mixed Methods Study.

BACKGROUND: Among the numerous factors contributing to health care providers' engagement with mobile apps, including user characteristics (eg, dexterity, anatomy, and attitude) and mobile features (eg, screen and button size), usability and quality of apps have been introduced as the most influential factors. OBJECTIVE: This study aims to investigate the usability and quality of the Head Computed Tomography Scan Appropriateness Criteria (HAC) mobile app for physicians' computed tomography scan ordering. METHODS: Our study design was primarily based on methodological triangulation by using mixed methods research involving quantitative and qualitative think-aloud usability testing, quantitative analysis of the Mobile Apps Rating Scale (MARS) for quality assessment, and debriefing across 3 phases. In total, 16 medical interns participated in quality assessment and testing usability characteristics, including efficiency, effectiveness, learnability, errors, and satisfaction with the HAC app. RESULTS: The efficiency and effectiveness of the HAC app were deemed satisfactory, with ratings of 97.8% and 96.9%, respectively. MARS assessment scale indicated the overall favorable quality score of the HAC app (82 out of 100). Scoring 4 MARS subscales, Information (73.37 out of 100) and Engagement (73.48 out of 100) had the lowest scores, while Aesthetics had the highest score (87.86 out of 100). Analysis of the items in each MARS subscale revealed that in the Engagement subscale, the lowest score of the HAC app was "customization" (63.6 out of 100). In the Functionality subscale, the HAC app's lowest value was "performance" (67.4 out of 100). Qualitative think-aloud usability testing of the HAC app found notable usability issues grouped into 8 main categories: lack of finger-friendly touch targets, poor search capabilities, input problems, inefficient data presentation and information control, unclear control and confirmation, lack of predictive capabilities, poor assistance and support, and unclear navigation logic. CONCLUSIONS: Evaluating the quality and usability of mobile apps using a mixed methods approach provides valuable information about their functionality and disadvantages. It is highly recommended to embrace a more holistic and mixed methods strategy when evaluating mobile apps, because results from a single method imperfectly reflect trustworthy and reliable information regarding the usability and quality of apps.

Pictorial Review of Cranial Nerve Denervation in the Head and Neck.

Of the twelve cranial nerves, nine supply motor innervation to the muscles of the head and neck. Loss of this motor nerve supply, or denervation, follows a series of predictable chronologic changes in the affected muscles. Although the length of time between each change is markedly variable, denervation is typically classified into three distinct time points: (a) acute, (b) subacute, and (c) chronic. These muscle changes produce characteristic findings on images, with contrast-enhanced MRI being the preferred modality for assessment. Imaging allows radiologists to not only identify denervation but also evaluate the extent of denervation and localize the potential site of insult. However, these findings may be easily mistaken for other diseases with similar manifestations, such as neoplasm, infection, and inflammatory conditions. As such, it is fundamental for radiologists to be familiar with cranial nerve anatomy and denervation patterns so that they can avoid these potential pitfalls and focus their imaging search on the pathway of the affected nerve. In this article, the anatomy and muscles innervated by motor cranial nerves in the head and neck, denervation, and the associated expected imaging patterns are reviewed, and examples of potential pitfalls and denervation mimics are provided. ©RSNA, 2024.

Customized Soft Tissue Free Flaps in Head and Neck Reconstruction.

The integration of imaging technologies such as computed tomography angiography and color Doppler ultrasonography are transforming soft tissue free flap reconstruction. The search for thinner and more refined flaps has expanded indications for flaps harvested from donor sites that were not commonly used in head and neck reconstruction. This article explores how these tools and techniques facilitate precise flap selection, thickness, and design customization based on detailed patient preoperative perforator anatomy and vascular configuration mapping. Optimizing outcomes with tailored flap designs improves surgical accuracy and patient-specific results in soft tissue reconstruction.

Scatter estimation and correction using time-of-flight and deconvolution in x-ray medical imaging.

Objective.Time-of-flight (TOF) scatter rejection requires a total timing jitter, including the detector timing jitter and the x-ray source's pulses width, of 50 ps or less to mitigate most of the effects of scattered photons in radiography and CT imaging. However, since the total contribution of the source and detector to the timing jitter can be retrieved during an acquisition with nothing between the source and detector, it can be demonstrated that this contribution may be partially removed to improve the image quality.Approach.A scatter correction method using iterative deconvolution of the measured time point-spread function estimates the number of scattered photons detected in each pixel. To evaluate the quality of the estimation, GATE was used to simulate the radiography of a water cylinder with bone inserts, and a head and torso in a system with total timing jitters from 100 ps up to 500 ps full-width-at-half-maximum (FWHM).Main results.With a total timing jitter of 200 ps FWHM, 89% of the contrast degradation caused by scattered photons was recovered in a head and torso radiography, compared to 28% with a simple time threshold method. Corrected images using the estimation have a percent root-mean square error between 2% and 14% in both phantoms with timing jitters from 100 to 500 ps FWHM which is lower than the error achieved with scatter rejection alone at 100 ps FWHM.Significance.TOF x-ray imaging has the potential to mitigate the effects of the scattering contribution and offers an alternative to anti-scatter grids that avoids loss of primary photons. Compare to simple TOF scatter rejection using only a threshold, the deconvolution estimation approach has lower requirements on both the source and detector. These requirements are now within reach of state-of-the-art systems.

A deep learning approach to identify the fetal head position using transperineal ultrasound during labor.

OBJECTIVES: To develop a deep learning (DL)-model using convolutional neural networks (CNN) to automatically identify the fetal head position at transperineal ultrasound in the second stage of labor. MATERIAL AND METHODS: Prospective, multicenter study including singleton, term, cephalic pregnancies in the second stage of labor. We assessed the fetal head position using transabdominal ultrasound and subsequently, obtained an image of the fetal head on the axial plane using transperineal ultrasound and labeled it according to the transabdominal ultrasound findings. The ultrasound images were randomly allocated into the three datasets containing a similar proportion of images of each subtype of fetal head position (occiput anterior, posterior, right and left transverse): the training dataset included 70 %, the validation dataset 15 %, and the testing dataset 15 % of the acquired images. The pre-trained ResNet18 model was employed as a foundational framework for feature extraction and classification. CNN1 was trained to differentiate between occiput anterior (OA) and non-OA positions, CNN2 classified fetal head malpositions into occiput posterior (OP) or occiput transverse (OT) position, and CNN3 classified the remaining images as right or left OT. The DL-model was constructed using three convolutional neural networks (CNN) working simultaneously for the classification of fetal head positions. The performance of the algorithm was evaluated in terms of accuracy, sensitivity, specificity, F1-score and Cohen's kappa. RESULTS: Between February 2018 and May 2023, 2154 transperineal images were included from eligible participants across 16 collaborating centers. The overall performance of the model for the classification of the fetal head position in the axial plane at transperineal ultrasound was excellent, with an of 94.5 % (95 % CI 92.0--97.0), a sensitivity of 95.6 % (95 % CI 96.8-100.0), a specificity of 91.2 % (95 % CI 87.3-95.1), a F1-score of 0.92 and a Cohen's kappa of 0.90. The best performance was achieved by the CNN1 - OA position vs fetal head malpositions - with an accuracy of 98.3 % (95 % CI 96.9-99.7), followed by CNN2 - OP vs OT positions - with an accuracy of 93.9 % (95 % CI 89.6-98.2), and finally, CNN3 - right vs left OT position - with an accuracy of 91.3 % (95 % CI 83.5-99.1). CONCLUSIONS: We have developed a DL-model capable of assessing fetal head position using transperineal ultrasound during the second stage of labor with an excellent overall accuracy. Future studies should validate our DL model using larger datasets and real-time patients before introducing it into routine clinical practice.

[Repeated Bow hunter's stroke by artery-to-artery embolism from the vertebral artery dissecting aneurysm formed by head rotation: A case report].

A 55-year-old woman suffered from diplopia and occipital pain after shoveling snow. She was diagnosed with the right vertebral artery dissecting aneurysm at the level of the axial vertebra and repeatedly had cerebral infarctions in the posterior circulation. She had subluxation of the atlantoaxial vertebra as an underlying disease. Right vertebral angiogram with the head rotated to the left showed the right vertebral artery occlusion and left vertebral angiogram with the head rotated to the right showed stenosis at the C1-C2 level, leading to the diagnosis of Bow hunter's stroke. After wearing a cervical collar and taking 100 |mg of aspirin, she had no recurrence of cerebral infarction and later underwent C1-C2 posterior fusion to prevent the recurrence of cerebral infarction. She finished taking aspirin 6 months after the surgery, and there has been no recurrence of cerebral infarction. We report here a case of Bow hunter's stroke, a rare disease, with good clinical outcomes after C1-C2 posterior fusion.

Dynamic contrast enhanced MRI of the head and neck region using a VIBE sequence with Cartesian undersampling and compressed sensing.

OBJECTIVES: Compressed sensing allows for image reconstruction from sparsely sampled k-space data, which is particularly useful in dynamic contrast enhanced MRI (DCE-MRI). The aim of the study was to assess the diagnostic value of a volume-interpolated 3D T1-weighted spoiled gradient-echo sequence with variable density Cartesian undersampling and compressed sensing (CS) for head and neck MRI. METHODS: Seventy-one patients with clinical indications for head and neck MRI were included in this study. DCE-MRI was performed at 3 Tesla magnet using CS-VIBE (variable density undersampling, temporal resolution 3.4 s, slice thickness 1 mm). Image quality was compared to standard Cartesian VIBE. Three experienced readers independently evaluated image quality and lesion conspicuity on a 5-point Likert scale and determined the DCE-derived time intensity curve (TIC) types. RESULTS: CS-VIBE demonstrated higher image quality scores compared to standard VIBE with respect to overall image quality (4.3 ± 0.6 vs. 4.2 ± 0.7, p = 0.682), vessel contour (4.6 ± 0.4 vs. 4.4 ± 0.6, p < 0.001), muscle contour (4.4 ± 0.5 vs. 4.5 ± 0.6, p = 0.302), lesion conspicuity (4.5 ± 0.7 vs. 4.3 ± 0.9, p = 0.024) and showed improved fat saturation (4.8 ± 0.3 vs. 3.8 ± 0.4, p < 0.001) and movement artifacts were significantly reduced (4.6 ± 0.6 vs. 3.7 ± 0.7, p < 0.001). Standard VIBE outperformed CS-VIBE in the delineation of pharyngeal mucosa (4.2 ± 0.5 vs. 4.6 ± 0.6, p < 0.001). Lesion size in cases where a focal lesion was identified was similar for all readers for CS-VIBE and standard VIBE (p = 0.101). TIC curve assessment showed good interobserver agreement (k=0.717). CONCLUSION: CS-VIBE with variable density Cartesian undersampling allows for DCE-MRI of the head and neck region with diagnostic, high image quality and high temporal resolution.

[Ultrasonographic features of Castleman disease in the head and neck: a report of 7 cases].

PURPOSE: To summarize the ultrasonographic features of head and neck Castleman disease (CD), and to clarify its diagnostic key points. METHODS: Seven patients with head and neck CD confirmed by histopathology were collected from Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine. The clinical features and ultrasound findings of the patients were evaluated. RESULTS: Of the 7 patients (1 male and 6 females), the mean age at diagnosis was 31.4 years (7-60 years). All the cases were hyaline vascular type. On ultrasound, 3 lesions (42.9%) were located in the parotid gland, 4 lesions(57.1%) in the neck. All the lesions presented as a solitary, well-defined and solid mass without calcification. The echogenicity was markedly hypoechoic in 1 case(14.3%) and hypoechoic in 6 cases (85.7%). Of the 7 CD cases, 4 cases (57.1%) were heterogeneous masses with linear echogenic septa. All lesions had mixed pattern in vascularity on color Doppler sonography. CONCLUSIONS: Most CDs in the head and neck represent as a markedly hypoechoic or hypoechoic lesion with mixed pattern in vascularity. The neoplasm may be characterized by the presence of linear echogenic septa within the mass.

ACSwinNet: A Deep Learning-Based Rigid Registration Method for Head-Neck CT-CBCT Images in Image-Guided Radiotherapy.

Accurate and precise rigid registration between head-neck computed tomography (CT) and cone-beam computed tomography (CBCT) images is crucial for correcting setup errors in image-guided radiotherapy (IGRT) for head and neck tumors. However, conventional registration methods that treat the head and neck as a single entity may not achieve the necessary accuracy for the head region, which is particularly sensitive to radiation in radiotherapy. We propose ACSwinNet, a deep learning-based method for head-neck CT-CBCT rigid registration, which aims to enhance the registration precision in the head region. Our approach integrates an anatomical constraint encoder with anatomical segmentations of tissues and organs to enhance the accuracy of rigid registration in the head region. We also employ a Swin Transformer-based network for registration in cases with large initial misalignment and a perceptual similarity metric network to address intensity discrepancies and artifacts between the CT and CBCT images. We validate the proposed method using a head-neck CT-CBCT dataset acquired from clinical patients. Compared with the conventional rigid method, our method exhibits lower target registration error (TRE) for landmarks in the head region (reduced from 2.14 ± 0.45 mm to 1.82 ± 0.39 mm), higher dice similarity coefficient (DSC) (increased from 0.743 ± 0.051 to 0.755 ± 0.053), and higher structural similarity index (increased from 0.854 ± 0.044 to 0.870 ± 0.043). Our proposed method effectively addresses the challenge of low registration accuracy in the head region, which has been a limitation of conventional methods. This demonstrates significant potential in improving the accuracy of IGRT for head and neck tumors.

Observed-to-expected lung-area-to-head-circumference ratio on ultrasound examination vs total fetal lung volume on magnetic resonance imaging in prediction of survival in fetuses with left-sided diaphragmatic hernia.

OBJECTIVE: To assess and compare the value of antenatally determined observed-to-expected (O/E) lung-area-to-head-circumference ratio (LHR) on ultrasound examination vs O/E total fetal lung volume (TFLV) on magnetic resonance imaging (MRI) examination to predict postnatal survival of fetuses with isolated, expectantly managed left-sided congenital diaphragmatic hernia (CDH). METHODS: This was a multicenter retrospective study including all consecutive fetuses with isolated CDH that were managed expectantly in Mannheim, Germany, and in five other European centers, that underwent at least one ultrasound examination for measurement of O/E-LHR and one MRI scan for measurement of O/E-TFLV during pregnancy. All MRI data were centralized, and lung volumes were measured by two experienced operators blinded to the pre- and postnatal data. Multiple logistic regression analyses were performed to examine the effect on survival at hospital discharge of various perinatal variables, including the center of management. In left-sided CDH with intrathoracic herniation of the liver, receiver-operating-characteristics (ROC) curves were constructed separately for cases from Mannheim and the other five European centers and were used to compare O/E-TFLV and O/E-LHR in the prediction of postnatal survival. RESULTS: From Mannheim, 309 patients were included with a median gestational age (GA) at ultrasound examination of 29.6 (range, 19.7-39.1) weeks and median GA at MRI examination of 31.1 (range, 18.0-39.9) weeks. From the other five European centers, 116 patients were included with a median GA at ultrasound examination of 26.7 (range, 20.6-37.6) weeks and median GA at MRI examination of 27.7 (range, 21.3-37.9) weeks. Regression analysis demonstrated that the survival rates at discharge were lower in left-sided CDH (odds ratio (OR), 0.349 (95% CI, 0.133-0.918), P = 0.033) and those with intrathoracic liver (OR, 0.297 (95% CI, 0.141-0.628), P = 0.001), and higher with increasing O/E-TFLV (OR, 1.123 (95% CI, 1.079-1.170), P < 0.001), advanced GA at birth (OR, 1.294 (95% CI, 1.055-1.588), P = 0.013) and when birth occurred in Mannheim (OR, 7.560 (95% CI, 3.368-16.967), P < 0.001). Given the difference in survival rate between Mannheim and the five other European centers, ROC curve comparisons between the two imaging modalities were presented separately. For cases of left-sided CDH with intrathoracic herniation of the liver, pairwise comparison showed no significant difference between the area under the ROC curves for the prediction of postnatal survival between O/E-TFLV and O/E-LHR in Mannheim (mean difference = 0.025, P = 0.610, standard error = 0.050), whereas there was a significant difference in the other European centers studied (mean difference = 0.056, P = 0.033, standard error = 0.056). CONCLUSIONS: In fetuses with left-sided CDH and intrathoracic herniation of the liver, the predictive value for postnatal survival of O/E-TFLV on MRI examination and O/E-LHR on ultrasound examination was similar in one center (Mannheim), but O/E-TFLV had better predictive value compared to O/E-LHR in the five other European centers. Hence, in these five European centers, MRI should be included in the diagnostic process for left-sided CDH. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

[Development of a Head Radiography Simulator System Using Pose Estimation Techniques].

PURPOSE: This study proposes a system that can simulate head radiography by combining a technique for estimating human posture from moving images (hereafter referred to as "pose estimation technique") and use of two cameras capable of acquiring RGB images to determine body position during positioning. METHODS: The angles of the median sagittal plane (MS), axial plane (AX), and orbitomeatal baseline (OM) were obtained using the pose estimation technique from frontal and lateral images captured after positioning. The resulting radiographs were displayed according to the results. RESULTS: The head tilt during positioning could be determined based on the coordinate data of feature points acquired using the pose estimation technique. In an imaging experiment using a simulated human patient, errors increased as head tilt increased; however, the mean error values in each axis were 0.9° for MS, 0.8° for AX, and 1.5°for OM, when the patient was correctly positioned. CONCLUSION: The pose estimation technique can assist in evaluating positioning accuracy in radiography and is expected to be used as a potential simulator system.

[Artifact Assessment in the Skull Base Region of Head CT Images with Various Tilt Angles Relative to the Orbitomeatal Line].

PURPOSE: The aim of this study was to evaluate artifacts in the skull base region of head computed tomography (CT) images with various tilt angles relative to the orbitomeatal line. METHODS: CT images of a head phantom acquired by helical and non-helical scanning with the tilt angles set from 0 to 20 degrees in 5-degree increments were evaluated in this study. Regions of interest (ROIs) were set at the cerebellum, temporal lobe, frontal lobe, and basal ganglia in the phantom images. Artifacts were evaluated by the coefficient of variation (CV) of the mean CT value between ROIs and the location parameter (ß) of the Gumbel method. RESULTS: The CV and ß values increased with increasing tilt angle for both helical and nonhelical images in the frontal lobes, but both decreased in the cerebellar region. In the temporal lobe and basal ganglia, there was no trend of change with tilt angle. CONCLUSION: Increasing the tilt angle relative to the OM line increased artifacts at the frontal lobes and decreased artifacts at the cerebellar region.

Complications of pediatric macrocystic lymphatic malformations of the head and neck: a survival analysis of treated and untreated patients.

OBJECTIVE: To compare events of recurrent swelling between treated and untreated patients with macrocystic lymphatic malformations of the head and neck not involving the airway. The frequency and timing of emergency department (ED) visits related to the event were analysed to provide data on efficacy and ideal timing of treatment. METHODS: A 5-year retrospective review of a hospital database was conducted reviewing 35 patients (15 female, 20 male; mean age 3.9 years) with macrocystic lymphatic malformations of the head and neck not involving the airway. Patients treated with oral medications were excluded. A survival analysis was performed comparing the incidence of recurrent swelling of the malformation. A Cox regression analysis was conducted using age, gender, diameter of lymphatic malformation at presentation, and echogenicity on US as covariates. Fisher's test and mean comparisons were performed to correlate the populations baselines and the number and frequency of ED visits between the 2 groups. RESULTS: Thirteen patients underwent sclerotherapy soon after initial presentation and 22 elected for observation. The two baseline populations differed at presentation with the treatment group being younger (1.4 ± 2.4 vs. 5.4 ± 6.3 years, p = 0.03) and with larger lesions (5.7 ± 2.7 vs. 4.0 ± 1.7 cm p = 0.03). Mean follow-up time was 2.7 years. Survival analysis showed 1 or multiple recurrences affected 16 patients in the untreated group and 3 patients in the treated group. (p = 0.04). Age, gender, diameter of the lesion at presentation and increased echogenicity on US were not predictive factors of recurrence. Although the probability of visiting the ED at least once did not differ between the two groups (p = 0.42), patients from the non-treatment group were more likely to visit the ED more than once (p = 0.03). CONCLUSIONS: Sclerotherapy treatment may reduce the chance of recurrent swelling or an event after initial presentation to the ED.

Distortion-free water-fat separated diffusion-weighted imaging using spatiotemporal joint reconstruction.

PURPOSE: Diffusion-weighted imaging (DWI) suffers from geometric distortion and chemical shift artifacts due to the commonly used Echo Planar Imaging (EPI) trajectory. Even with fat suppression in DWI, severe B0 and B1 variations can result in residual fat, which becomes both a source of image artifacts and a confounding factor in diffusion-weighted contrast in distinguishing benign and malignant tissues. This work presents a method for acquiring distortion-free diffusion-weighted images using spatiotemporal acquisition and joint reconstruction. Water-fat separation is performed by chemical-shift encoding. METHODS: Spatiotemporal acquisition is employed to obtain distortion-free images at a series of echo times. Chemical-shift encoding is used for water-fat separation. Reconstruction and separation are performed jointly in the spat-spectral domain. To address the shot-to-shot motion-induced phase in DWI, an Fast Spin Echo (FSE)-based phase navigator is incorporated into the sequence to obtain distortion-free phase information. The proposed method was validated in phantoms and in vivo for the brain, head and neck, and breast. RESULTS: The proposed method enables the acquisition of distortion-free diffusion-weighted images in the presence of B0 field inhomogenieties commonly observed in the body. Water and fat components are separated with no obvious spectral leakage artifacts. The estimated Apparent Diffusion Coefficient (ADC) is comparable to that of multishot DW-EPI. CONCLUSION: Distortion-free, water-fat separated diffusion-weighted images in body can be obtained through the utilization of spatiotemporal acquisition and joint reconstruction methods.

Photon-Counting CT in the Head and Neck: Current Applications and Future Prospects.

Photon-counting detectors (PCDs) represent a major milestone in the evolution of CT imaging. CT scanners using PCD systems have already been shown to generate images with substantially greater spatial resolution, superior iodine contrast-to-noise ratio, and reduced artifact compared with conventional energy-integrating detector-based systems. These benefits can be achieved with considerably decreased radiation dose. Recent studies have focused on the advantages of PCD-CT scanners in numerous anatomic regions, particularly the coronary and cerebral vasculature, pulmonary structures, and musculoskeletal imaging. However, PCD-CT imaging is also anticipated to be a major advantage for head and neck imaging. In this paper, we review current clinical applications of PCD-CT in head and neck imaging, with a focus on the temporal bone, facial bones, and paranasal sinuses; minor arterial vasculature; and the spectral capabilities of PCD systems.

Selective postmortem arterial angiography of head and neck using digital x-ray or computed tomography: A practical and rapid method to identify vascular injuries.

Identification of vascular injuries is crucial for complete postmortem evaluation and understanding of trauma deaths by the Medical Examiner. Some vascular injuries are difficult to evaluate due to challenging anatomic locations, especially in the head and neck. Documenting injuries of the facial and vertebral arteries is challenging and necessitates time-consuming dissections that can create artifacts and disfigurement. In busy medical examiner offices with a significant number of traumatic injuries, finding a creative solution to employ reliable postmortem angiography is desirable. At the Office of the Chief Medical Examiner for the State of Maryland (OCME), we created and effectively implemented a selective angiography procedure using traditional indwelling Foley catheters and water-soluble barium swallow contrast to evaluate arterial injuries using either digital radiography or computed tomography imaging modalities. This technique and imaging interpretation can be performed by a medical examiner or forensic pathology fellow after basic technical training and basic radiology training. This study outlines the technique, methods, and utilization of the procedure and describes the findings of six deaths due to vascular lesions from different injury mechanisms and disease processes and describes the ease of implementation on a broader scale in busy Medical Examiner's offices.