Cervical Osteomyelitis and Diskitis as a Complication of Neopharyngeal Breakdown: A Multisite Case Series Review.

Laryngectomy and pharyngectomy are surgical options for advanced laryngeal or pharyngeal squamous cell carcinoma. Cervical osteomyelitis-diskitis, occurring when there is dehiscence of the posterior neopharyngeal wall, is an uncommon complication of laryngopharyngectomy. This case series describes imaging findings of pharyngoesophageal wall breakdown with subsequent cervical spine infection and demonstrates that most of these patients had undergone prior esophageal or neopharyngeal dilations for benign posttreatment stricture. Neck pain, fever, or serologic evidence of infection should prompt careful evaluation for osteomyelitis-diskitis and assessment for neopharyngeal breakdown and sinus tract formation, especially in the postdilation setting.

Diffusion-Weighted Imaging of the Orbit: A Case Series and Systematic Review.

PURPOSE: To describe the findings of diffusion-weighted imaging (DWI) for a series of orbital lesions and provide a systematic review of relevant literature. METHODS: A retrospective review of 20 patients with orbital lesions who underwent MRI with DWI at two academic institutions between 2015 and 2020 was performed. Lesion diagnosis was histopathologically confirmed except a presumed cavernous hemangioma. Echoplanar diffusion-weighted images had been acquired using 2 or 3 b values (b=0 and 1000 or b=0, 500, and 1000) at 1.5T or 3T. Lesions with significant artifacts were excluded. DWI sequences were analyzed by neuro-radiologists blinded to the diagnosis. Mean ADC values of lesions were calculated from a single region of interest. An independent two-tailed t test was used to compare categories of lesions with p < 0.05 considered significant. A systematic review of the literature was performed. RESULTS: Our study included 21 lesions. ADC values were significantly lower for malignant lesions (0.628 ± 0.125 × 10 -3 mm 2 /s) than inflammatory lesions (1.167 ± 0.381 × 10 -3 mm 2 /s) ( p < 0.001). ADC values were significantly lower for orbital lymphoma (mean 0.621 ± 0.147 × 10 -3 mm 2 /s) than idiopathic orbital inflammation (mean 1.188 ± 0.269 × 10 -3 mm 2 /s) with no overlap ( p < 0.001). CONCLUSIONS: Orbital malignancies demonstrated lower ADC values, while inflammatory processes demonstrated higher ADC values, except IgG4-related disease. DWI and ADC values differentiated idiopathic orbital inflammation from orbital lymphoma. This study highlights the role of DWI in evaluating orbital pathology.

Deep learning versus iterative reconstruction on image quality and dose reduction in abdominal CT: a live animal study.

Objective.While simulated low-dose CT images and phantom studies cannot fully approximate subjective and objective effects of deep learning (DL) denoising on image quality, live animal models may afford this assessment. This study is to investigate the potential of DL in CT dose reduction on image quality compared to iterative reconstruction (IR).Approach.The upper abdomen of a live 4 year old sheep was scanned on a CT scanner at different exposure levels. Images were reconstructed using FBP and ADMIRE with 5 strengths. A modularized DL network with 5 modules was used for image reconstruction via progressive denoising. Radiomic features were extracted from a region over the liver. Concordance correlation coefficient (CCC) was applied to quantify agreement between any two sets of radiomic features. Coefficient of variation was calculated to measure variation in a radiomic feature series. Structural similarity index (SSIM) was used to measure the similarity between any two images. Diagnostic quality, low-contrast detectability, and image texture were qualitatively evaluated by two radiologists. Pearson correlation coefficient was computed across all dose-reconstruction/denoising combinations.Results.A total of 66 image sets, with 405 radiomic features extracted from each, are analyzed. IR and DL can improve diagnostic quality and low-contrast detectability and similarly modulate image texture features. In terms of SSIM, DL has higher potential in preserving image structure. There is strong correlation between SSIM and radiologists' evaluations for diagnostic quality (0.559) and low-contrast detectability (0.635) but moderate correlation for texture (0.313). There is moderate correlation between CCC of radiomic features and radiologists' evaluation for diagnostic quality (0.397), low-contrast detectability (0.417), and texture (0.326), implying that improvement of image features may not relate to improvement of diagnostic quality.Conclusion.DL shows potential to further reduce radiation dose while preserving structural similarity, while IR is favored by radiologists and more predictably alters radiomic features.

Normal Vascular Structures and Variants on Head and Neck Imaging.

The vasculature of the neck, comprised of arteries and veins, provides for the supply and return of blood to and from the brain, and to structures of the neck and face. Knowledge of normal appearance and anatomy, and anatomic variants, may help one distinguish between normal and pathologic processes in the neck, which may affect diagnosis or choice of surgical approach. Other related structures that are important to recognize include the thoracic duct and carotid body. In this article examples of mostly computed tomography and MR imaging of normal anatomy and some of these variants are shown.

Iterative Reconstruction in Dose Reduction of A Head CT Examination and Corresponding Acquisition Parameter Selection.

PURPOSE: To investigate the potential of iterative reconstruction in radiation dose reduction during head computed tomography (CT) examinations and to evaluate the relationship between the parameters milliampere second (mAs), kilovoltage (kV), and iterative reconstruction strength using a live ovine (sheep) model. METHODS: A sheep was scanned on a SOMATOM Force (Siemens Healthineers) CT scanner at 12 mAs and 3 kV. Images were reconstructed with filtered back projection (FBP) and the Advanced Modeled Iterative Reconstruction (ADMIRE; Siemens Healthineers) strengths 1 to 5. Images with 216 combinations of varying doses, kVs, and reconstructions were rated by 2 neuroradiologists for low-contrast detectability (ie, gray-white matter differentiation) and image texture. RESULTS: Using only gray-white matter differentiation, maximum dose reduction was 75% at 100 kV with ADMIRE-3, and using only image texture, maximum dose reduction was 75% at 120 kV (and 140 kV) with ADMIRE-5. When these 2 metrics were combined, maximum dose reduction was 50% at 120 kV with ADMIRE-3. Other kV levels and higher iterative reconstruction strengths did not offer superior results. DISCUSSION: Although artificial intelligence algorithms are certainly gaining momentum, iterative reconstruction technology likely will remain more accessible to most hospitals and imaging centers. Dose reduction with preservation of image quality (ie, gray-white differentiation and image texture) can be achieved when complemented by appropriate iterative reconstruction strength. However, the effect of iterative reconstruction strength on gray-white differentiation and image texture does not necessarily converge on the same pattern. CONCLUSION: Maximum dose reduction was 50% at 120 kV with ADMIRE-3, which confirms the potential for dose reduction with appropriately chosen iterative reconstruction strength and reveals a preference for 120 kV, as well as a limit to dose reduction by further increasing iterative reconstruction strength. A better understanding of dose-voltage-reconstruction relationships in iterative reconstruction might allow for greater dose reductions than current practices allow.

Prediction of recurrent glioblastoma after laser interstitial thermal therapy: The role of diffusion imaging.

BACKGROUND: Evaluate the utility of diffusion-weighted imaging (DWI) for the assessment of local recurrence of glioblastoma (GBM) on imaging performed 24 h following MRI-guided laser interstitial thermal therapy (LITT). We hypothesize that microscopic peritumoral infiltration correlates with early subtle variations on DWI images and apparent diffusion coefficient (ADC) maps. METHODS: Of 64 patients with GBM treated with LITT, 39 had MRI scans within 24 h after undergoing LITT. Patterns on DWI images and ADC maps 24 h following LITT were correlated with areas of future GBM recurrence identified through coregistration of subsequent MRI examinations. In the areas of suspected recurrence within the periphery of post-LITT lesions, signal intensity values on ADC maps were recorded and compared with the remaining peritumoral ring. RESULTS: Thirty-nine patients with GBM met the inclusion criteria. For predicting recurrent GBM, areas of decreased DWI signal and increased signal on ADC maps within the expected peritumoral ring of restricted diffusion identified 24 h following LITT showed 86.1% sensitivity, 75.2% specificity, and high correlation (r = 0.53) with future areas of GBM recurrence (P < .01). Areas of future recurrence demonstrated a 37% increase in the ADC value (P < .001), compared with findings in the surrounding treated peritumoral region. A significantly greater area under the receiver operating characteristics curve was determined for ADC values (P < .01). CONCLUSIONS: DWI obtained 24 h following LITT can help predict the location of GBM recurrence months before the development of abnormal enhancement. This may alter future treatment planning, perhaps suggesting areas that may be targeted for additional therapy.

Rehabilitation outcomes after combined acute disseminated encephalomyelitis and Guillain-Barré syndrome in a child: a case report.

A 5-year old female presented with acute tetraparesis and areflexia. Initial imaging and cerebrospinal fluid analysis were suggestive of acute disseminated encephalomyelitis (ADEM). Minimal clinical response with intravenous steroids prompted further work up. Limited nerve conduction studies suggested possible acute motor-sensory axonal neuropathy, a rare variant of Guillain-Barré syndrome (GBS). Repeat imaging was compatible with polyradiculopathy indicating concomitance of ADEM and GBS. The patient suffered severe motor deficits and neuropathic pain. Slow but significant functional recovery was noted after intensive inpatient rehabilitation followed by continued rehabilitation via home health services.

Macroglossia in amyotrophic lateral sclerosis.

IMPORTANCE: We encountered 2 patients with amyotrophic lateral sclerosis (ALS) with tongue enlargement and protrusion outside the oral cavity (macroglossia). To our knowledge, the relationship between macroglossia and ALS has not been reported in the literature. The objective of this article was to describe the clinical characteristics, imaging, and pathology of macroglossia in ALS and to develop a hypothesis regarding its pathophysiology. OBSERVATIONS: Two patients developed progressive weakness at age 54 and 40 years. Both patients exhibited dysarthria, dysphagia, tongue atrophy, neck extensor weakness, and weakness of jaw closure during a 1-year period. Both required tracheostomy and mechanical ventilation and afterward developed macroglossia. A 3-dimensional-reconstructed sagittal computed tomographic image confirmed tongue protrusion outside the oral cavity with focal compression and showed the transition from the atrophied part of the tongue in the oropharynx to the edematous part outside the mouth. Tongue biopsy demonstrated fatty replacement and fascicles of degenerative muscle. CONCLUSIONS AND RELEVANCE: We are unaware of previous reports of macroglossia in ALS/motor neuron disease. Given the paucity of case material, we speculated that this is an extremely rare complication of ALS. Based on this series, we propose a pathophysiological mechanism by reviewing imaging and tongue biopsy.

Role of positron emission tomography/computed tomography (PET/CT) in head and neck cancer.

Positron emission tomography/computed tomography (PET/CT) has an important role in the diagnosis and treatment of head and neck cancer. The technique can aid in the detection of an unknown primary tumor, assist in locoregional staging, evaluate for distant metastases or second primary tumors, and be a component of restaging and tumor surveillance. This article reviews the basic principles, pitfalls, and uses of PET/CT in head and neck cancer, as well as potential future applications.

Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids following influenza vaccination.

Inflammatory processes within the central nervous system are challenging for the clinician, radiologist, and pathologist alike. They often can mimic other more well-known and defined disease processes. We present the case of a patient with a newly described inflammatory process that primarily involves the pons and adjacent structures, which is called chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS). An 80-year-old man presented with numbness of his right hand that ultimately progressed to involve both lower extremities and face and was associated with mild dysarthria and ataxia. He had received the influenza vaccination 2 weeks prior. The biopsy revealed primarily reactive T-cell lymphocytic infiltrates with macrophages and gliosis. Treatment required long-term immunosuppressive therapy. CLIPPERS is a recently described central nervous system inflammatory condition that should be considered in the differential diagnosis when a prominent lymphocytic inflammatory infiltrate is encountered in brainstem, spinal cord, midbrain, or cerebellar biopsies.

Categorization and characterization of lesions of the orbital apex.

INTRODUCTION: The apex of the orbit is formed by the union of the lesser and greater wings of the sphenoid bone and acts as an osseous tunnel for numerous neurovascular structures entering the orbit from the cranial vault. Lesions of the orbital apex are clinically important as they can have an adverse effect on vision. A broad range of lesions can occur here, and our purpose is to organize the pathologic processes which occur in the orbital apex into logical imaging differentials, establish an organized approach to image analysis, and present examples of representative lesions. METHODS: We review the anatomy of the orbital apex and categorize and describe the pathologic entities that are encountered most frequently in this anatomically compact region and identify imaging patterns that can help to narrow the differential diagnosis. RESULTS: Categories of orbital apex lesions include neoplasms, inflammatory processes, infections, lesions causing extrinsic compression, and vascular lesions. This categorization provides an organized framework to facilitate a reasonable differential diagnosis. Computed tomography and magnetic resonance imaging are the modalities of choice to evaluate and characterize orbital apex lesions, and imaging examples utilizing these modalities will be presented. CONCLUSION: The orbital apex is a clinically important anatomical region and hosts diverse pathologic processes. An awareness of common imaging patterns can help to generate a focused differential diagnosis. A systematic categorical approach can be of help to radiologists attempting to accurately characterize lesions in this area.

Clinical usefulness of positron emission tomography-computed tomography in recurrent thyroid carcinoma.

OBJECTIVES: To determine the efficacy of combined positron emission tomography-computed tomography (PET-CT) in identifying recurrent thyroid cancer and to elucidate its role in the clinical management of thyroid carcinoma. DESIGN: Retrospective study. SETTING: Tertiary care referral academic center. PATIENTS: One hundred twenty-four patients with previously treated thyroid carcinoma who underwent PET-CT. MAIN OUTCOME MEASURES: PET-CT images were correlated with clinicopathologic information. The influence of PET-CT findings on disease status determination and the treatment plan was evaluated. RESULTS: Among 121 patients undergoing iodine I 131 ((131)I) imaging (an (131)I image was unavailable for 3 patients), 80.6% had negative findings on (131)I imaging before undergoing PET-CT. Among 75 patients who had positive findings on PET-CT, 71 were true positive results. Among 49 patients who had negative findings on PET-CT, 32 were true negative results. Therefore, PET-CT demonstrated a sensitivity of 80.7%, specificity of 88.9%, positive predictive value of 94.7%, and negative predictive value of 65.3%. A significant difference was noted in the mean serum thyroglobulin levels between patients with positive vs negative PET-CT findings (192.1 vs 15.0 ng/mL, P = .01) (to convert thyroglobulin level to micrograms per liter, multiply by 1.0). Overall, distant metastases were detected in 20.2% of patients using PET-CT. There was an alteration of the treatment plan in 28.2% of patients as a result of added PET-CT information, and 21.0% of patients underwent additional surgery. CONCLUSIONS: PET-CT is usually performed in patients with thyroid cancer having elevated thyroglobulin levels but non-(131)I-avid tumors and has high diagnostic accuracy for identifying local, regional, and distant metastases. Additional information from PET-CT in patients with (131)I-negative and thyroglobulin-positive tumors frequently guides the clinical management of recurrent thyroid carcinoma.

Appearance of normal cranial nerves on steady-state free precession MR images.

As radiologic imaging technology improves and more intricate details of the anatomy can be evaluated, images provide more precise diagnostic information and allow better localization of abnormalities. For example, standard T2-weighted magnetic resonance (MR) imaging sequences adequately depicted only the larger cranial nerves, whereas current steady-state free precession (SSFP) sequences are capable of depicting the cisternal segments of all 12 cranial nerves. SSFP sequences provide submillimetric spatial resolution and high contrast resolution between cerebrospinal fluid and solid structures, allowing the reconstruction of elegant multiplanar images that highlight the course of each nerve. These sequences have become a mainstay in the evaluation of the cerebellopontine angles and inner ear. Usually referred to by their trade names or acronyms (eg, constructive interference steady state, or CISS, and fast imaging employing steady-state acquisition, or FIESTA), SSFP sequences allow precise differentiation between branches of the facial and vestibulocochlear nerves, accurate detection of small masses in the cerebellopontine angles and internal auditory canals, and detailed evaluation of endolymph and perilymph within the inner ear. To take full advantage of these imaging sequences, radiologists must be familiar with the appearances of similar anatomic details of all 12 cranial nerves on SSFP MR images.

Positron emission tomography-computed tomography protocol considerations for head and neck cancer imaging.

Positron emission tomographic-computed tomographic (PET-CT) imaging of patients with primary head and neck cancers has become an established approach for staging and restaging, as well as radiation therapy planning. The inherent co-registration of PET and CT images made possible by the integrated PET-CT scanner is particularly valuable in head and neck cancer imaging due to the complex and closely situated anatomy in this part of the body, the varied sources of physiologic and benign 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) tracer uptake that occurs in the neck, and the varied and complex posttreatment appearance of the neck. Careful optimization of both the CT and the PET portion of the examination is essential to insure the most accurate and clinically valuable interpretation of these examinations.

Imaging of tinnitus.

From a radiologic workup perspective, tinnitus is classified into pulsatile, which can be objective, and nonpulsatile, which is typically subjective. There is considerable discrepancy within the literature regarding the percentage of positive findings in patients with pulsatile tinnitus. The authors discuss the overlap in the radiographic findings detected in association with tinnitus in both asymptomatic patients and symptomatic patients and the importance for imaging to detect treatable causes. They discuss imaging related to diagnosis and treatment and provide an imaging workup algorithm.

Normal CT appearance of the distal thoracic duct.

OBJECTIVE: The aims of this study were to determine how often the distal thoracic duct can be identified on neck CT and to characterize the CT appearance of the duct. MATERIALS AND METHODS: In a review of electronic medical records from January 2001 to January 2003 we identified the cases of 500 patients who had undergone CT of the neck. Because they had confounding factors such as cancer or cervical lymphadenopathy, 199 of these patients were excluded, leaving 301 patients in the study: 131 (44%) male patients and 170 (56%) female patients. The age range was 11-92 years (average age, 46 years). Two head and neck radiologists used strict diagnostic criteria and consensus to identify the distal thoracic duct on both sides of the neck. One half of the images selected at random were flipped left to right. The purpose of randomization was to avoid interpretation bias, because the thoracic duct is known to typically course within the left side of the neck. The configuration of the distal duct was tabulated, and effects of age and sex were statistically evaluated. RESULTS: The left side of the neck was unevaluable in 26 (9%) of 301 patients because of streak artifact. In the other 275 patients, the distal thoracic duct was identified in the left side of the necks of 150 (55%) of the patients. Eleven of these patients (4%) also had a visible duct in the right side of the neck, but a right-sided duct was never identified without a left-sided counterpart. The distal thoracic duct had a tubular configuration in 70 (43%), a flared configuration in 72 (45%), and a long segmental fusiform dilation in 19 (12%) of 161 patients. Patient sex had no significant effect on the appearance of the distal thoracic duct. Older patient age had a slight positive effect on the size of the duct. CONCLUSION: Familiarity with the normal CT appearance of the distal thoracic duct can be helpful in differentiating a normal duct from pathologic lesions of the lower neck, such as lymphadenopathy.