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.

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.

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.

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.

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.

It's not a cervical lymph node, it's a vein: CT and MR imaging findings in the veins of the head and neck.

The anatomy and imaging appearances of the veins of the head and neck can vary considerably, and normal veins may mimic disease processes at computed tomography (CT) and magnetic resonance (MR) imaging. On unenhanced CT scans, aberrant veins may be difficult to differentiate from lymph nodes or other pathologic conditions. Even at contrast material-enhanced CT, differences in venous enhancement or the mixing of opacified with nonopacified blood can lead to confusion, particularly if the vein is focally dilated. Similarly, the size and signal intensity of head and neck veins may vary at MR imaging due to slow or turbulent flow or variable enhancement, resulting in misdiagnosis. A thorough understanding of the normal venous anatomy and common variants is necessary to properly differentiate an unopacified or focally dilated vein from lymphadenopathy or some other disease entity and can help the radiologist avoid the erroneous interpretation of findings.

Superior semicircular canal dehiscence: oblique reformatted CT images for diagnosis.

PURPOSE: To retrospectively determine, by using thin-section multi-detector row computed tomography (CT), whether additional reformations in the planes of Stenver and Pöschl change the diagnostic interpretation for superior semicircular canal dehiscence (SSCD) when compared with the diagnostic interpretation of standard coronal reformations for SSCD. MATERIALS AND METHODS: Institutional review board approval was obtained, patient anonymity was maintained, and the study was HIPAA compliant. Twenty-seven patients (17 men, 10 women; average age, 45 years; range, 19-72 years) suspected of having SSCD who underwent temporal bone multi-detector row CT were retrospectively identified from electronic medical records. An additional 27 control subjects (nine men, 18 women; average age, 50 years; range, 18-87 years), who underwent temporal bone multi-detector row CT for other reasons, were retrospectively selected from the same period. Two neuroradiologists with certificates of added qualification, one with 5 years and one with 9 years of experience interpreting temporal bone CT images, independently reviewed the 108 temporal bones twice. One review was restricted to transverse images and coronal reformations. The other review used transverse images, coronal reformations, and oblique reformations in the planes of Stenver and Pöschl. The observers were blinded to clinical history, and the two reviews took place 3 months apart to avoid recall bias. The primary outcome measure was the intraobserver discordance rate between the two reviews. kappa Statistics were used to evaluate both intraobserver and interobserver variability. RESULTS: Observer 1 diagnosed SSCD in 25 of 108 (23%) temporal bones and had no discordances between the two reviews. Observer 2 diagnosed SSCD in 21 of 108 (19%) temporal bones and had one intraobserver discordance. After a post hoc consensus review of this one discordance, the radiologic diagnosis remained equivocal. The discordance involved the right temporal bone of a patient suspected of having SSCD in the left temporal bone, so no clinical follow-up was available. CONCLUSION: Coronal reformations from multi-detector row CT of the temporal bone are sufficient for the evaluation of SSCD. Additional reformations in the planes of Stenver and Pöschl do not change the radiologic diagnosis and may be reserved for equivocal or confusing cases.

Informatics in radiology (infoRAD): free DICOM image viewing and processing software for the Macintosh computer: what's available and what it can do for you.

It is often necessary for radiologists to use digital images in presentations and conferences. Most imaging modalities produce images in the Digital Imaging and Communications in Medicine (DICOM) format. The image files tend to be large and thus cannot be directly imported into most presentation software, such as Microsoft PowerPoint; the large files also consume storage space. There are many free programs that allow viewing and processing of these files on a personal computer, including conversion to more common file formats such as the Joint Photographic Experts Group (JPEG) format. Free DICOM image viewing and processing software for computers running on the Microsoft Windows operating system has already been evaluated. However, many people use the Macintosh (Apple Computer) platform, and a number of programs are available for these users. The World Wide Web was searched for free DICOM image viewing or processing software that was designed for the Macintosh platform or is written in Java and is therefore platform independent. The features of these programs and their usability were evaluated. There are many free programs for the Macintosh platform that enable viewing and processing of DICOM images.

Naturally acquired West Nile virus encephalomyelitis in transplant recipients: clinical, laboratory, diagnostic, and neuropathological features.

BACKGROUND: In the 2003 West Nile virus (WNV) epidemic, Colorado reported more WNV cases than any other state, including an unprecedented number in organ transplant recipients. METHODS: Physicians caring for transplant recipients hospitalized with naturally acquired WNV encephalitis provided data to characterize the clinical symptoms, results of diagnostic studies, and outcomes. RESULTS: Eleven transplant recipients were identified (4 kidney, 2 stem cell, 2 liver, 1 lung, and 2 kidney/pancreas). Seven were directly admitted to 1 of the 2 hospitals in the study, and 4 were referred to 1 of these centers from regional hospitals. All but 1 patient had a prodrome typical of WNV encephalitis in nonimmunosuppressed patients. Ten patients developed meningoencephalitis, which in 3 cases was associated with acute flaccid paralysis. One patient developed acute flaccid paralysis without encephalitis. Six patients had significant movement disorders including tremor, myoclonus, or parkinsonism. All patients had cerebrospinal fluid pleocytosis and WNV-specific IgM in the cerebrospinal fluid and/or serum. Cerebrospinal fluid cytologic studies (n = 5) showed atypical lymphocytes, some resembling plasma cells; however, flow cytometry (n = 3) showed that cells were almost exclusively of T-cell (not B-cell or plasma cell) lineage. Magnetic resonance images of the brain were abnormal in 7 of 8 tested patients, and electroencephalograms were abnormal in 7 of 7, with 2 showing periodic lateralized epileptiform discharges. Nine of 11 patients survived infection, but 3 had significant residual deficits. One patient died 17 days after admission, and autopsy findings revealed severe panencephalitic changes with multifocal areas of necrosis in the cerebral deep gray nuclei, brainstem, and spinal cord as well as diffuse macrophage influx in the periventricular white matter. A second patient died of complications of WNV encephalitis 6 months after hospital admission. CONCLUSIONS: Naturally acquired WNV encephalitis in transplant recipients shows diagnostic, clinical, and laboratory features similar to those reported in nonimmunocompromised individuals, but neuroimaging, electroencephalography, and autopsy results verify that these patients develop neurological damage at the severe end of the spectrum.

Proximal nerve root spinal hemangioblastomas: presentation of three cases, MR appearance, and literature review.

BACKGROUND: Hemangioblastomas (HBLs) are relatively uncommon tumors of uncertain histogenesis usually located in the cerebellum or spinal cord. Much less frequently they are identified in extramedullary locations including the filum terminale, proximal nerve roots, or even distal nerves of the peripheral nervous system (PNS). PNS cases not only present diagnostic challenges but also raise interesting questions regarding the common cell of origin for these CNS and PNS neoplasms. Few studies have detailed the neuroimaging characteristics of the rare extramedullary variants. METHODS: Neuroimaging and intraoperative findings of three recent cases of proximal nerve root HBLs are described. The English language literature on extramedullary HBLs is reviewed and discussed, particularly in regards to magnetic resonance (MR) findings and association with von Hippel-Lindau Syndrome (VHL). RESULTS: All 3 of our cases had prominent vessels present within the subarachnoid space on MR scans and all lesions enhanced. All were of intermediate or mildly decreased signal intensity on the T1-weighted images before contrast and were either iso- or hyperintense to spinal cord on the T2-weighted images. Two had probable cystic areas on MR, and all had cystic areas on histologic evaluation. CONCLUSION: These neuroimaging characteristics can serve to distinguish HBLs from the more common benign nerve sheath tumors with which they are most frequently confused. Less than half of all extramedullary HBLs are diagnosed in patients with known VHL. It is important to consider HBLs in the differential diagnosis, as they are vascular and have the propensity for causing significant blood loss at surgery.