Anatomical Parameters and Growth of the Pediatric Skull Base: Endonasal Access Implications.

Objectives Endoscopic endonasal anterior skull base surgery has expanding use in the pediatric population, but the anatomy of pediatric patients can lead to limitations. This study aims to characterize the important anatomical implications of the pediatric skull base using computed tomography (CT) scans. Design This study is designed as retrospective analysis. Setting The study setting comprises of tertiary academic medical center. Participants In total, 506 patients aged 0 to 18 who had undergone maxillofacial and or head CTs between 2009 to 2016 were involved. Methods Measurements included piriform aperture width, nare to sella distance (NSD), sphenoid pneumatization, olfactory fossa depth, lateral lamella cribriform plate angles, and intercarotid distances (ICD) at the superior clivus and cavernous sinus. These patients were then subdivided into three age groups adjusting for sex. Analysis of covariance (ANCOVA) models were fit comparing between all age groups and by sex. Results Piriform aperture width, NSD, sphenoid sinus pneumatization as measured using lateral aeration and anterior sellar wall thickness, olfactory fossa depth, and ICD at the cavernous sinus were significantly different among all age groups ( p <0.0001). Our results show that mean piriform aperture width increased with each age group. The mean olfactory fossa depth also had consistent age dependent growth. In addition, ICD at the cavernous sinus showed age dependent changes. When comparing by sexes, females consistently showed smaller measurements. Conclusion The process of skull base development is age and sex dependent. During preoperative evaluation of pediatric patients for skull base surgery piriform aperture width, sphenoid pneumatization in both the anterior posterior and lateral directions, and ICD at the cavernous sinus should be carefully reviewed.

Skull Base Anatomy in Patients with Bilateral Choanal Atresia: A Radiographic Study.

Introduction The risk of skull base injury during choanal atresia repair can be mitigated via thorough understanding of skull base anatomy. There is a paucity of data describing differences in skull base anatomy between patients with coloboma, heart defects, atresia choanae, growth retardation, genital abnormalities, and ear abnormalities (CHARGE) syndrome and those without. Objectives The aim of this study was to measure nasal and skull base anatomy in patients with isolated bilateral choanal atresia (BCA), CHARGE syndrome, and other syndromic congenital anomalies. Methods Retrospective chart review of patients with bilateral choanal atresia and computed tomography of the face between 2001 and 2019 were evaluated. Choanal width, height, mid-nasal height, and skull base slope were measured radiographically. Differences in anatomy between healthy patients, those with CHARGE syndrome, and those with other congenital anomalies were compared. Results Twenty-one patients with BCA and relevant imaging were identified: 7 with isolated BCA, 6 with CHARGE syndrome, and 8 with other congenital anomalies. A t -test indicated insignificant difference in skull base slope, choanal height, choanal width, or mid-nasal skull base height between isolate BCA cases and patients with any congenital anomaly. When comparing CHARGE to isolated BCA cases, mid-nasal height was shorter in CHARGE patients ( p = 0.03). There were no differences in measurements between patients with congenital anomalies excluding CHARGE ( p > 0.05). Two patients in the congenital anomaly group were found to have bony skull base defects preoperatively. Conclusion This study represents the largest description of skull base and nasal anatomy in patients with CHARGE syndrome and BCA. Surgeons should be aware of the lower skull base in CHARGE patients to avoid inadvertent skull base injury.

A Comprehensive Update of the Incidence and Demographics of Laryngoceles in Adults.

OBJECTIVE: To provide updated data on the incidence, types, and demographics of laryngoceles in the adult population. METHODS: We searched the medical archives of our institute for computed tomography (CT) studies acquired between January 1, 2007 and December 31, 2017 in which the term "laryngocele" appeared in the radiology reports. Two of the authors reviewed relevant images for the presence, type, distribution, and laterality of true laryngoceles. Demographic and clinical data were extracted from medical records and the incidence was calculated. RESULTS: Laryngoceles were detected in 53 out of the 79 893 patients with relevant CT data, which equates to an incidence of 151 per 2.5 million (0.06:1000) patients per year. The male:female ratio was 3:1, average age was 60 (±18) years, and incidence peaked among patients in the sixth decade of life. Nine patients (17%) had known laryngeal cancer; however, the majority of the cohort did not have follow up clinic visits. CONCLUSION: Our study demonstrates that the incidence of laryngoceles is much greater than previously reported. In most cases, the diagnosis of a laryngocele was an incidental radiological finding. Male gender predilection and age at presentation are in agreement with previous reports. Association of laryngoceles with laryngeal cancer could not be calculated due to low rates of follow ups. LEVEL OF EVIDENCE: 3.

Radiotheragnostics Paradigm for Radioactive Iodine (Iodide) Management of Differentiated Thyroid Cancer.

This review of radioactive iodide treatment (RAIT) extends from historical origins to its modern utilization in differentiated thyroid cancer (DTC). The principles embedded in the radiotheragnostics (RTGs) paradigm are detailed. The diverse approaches in current practice are addressed, and this broad variability represents a major weakness that erodes our specialty's trust-based relationship with patients and referring physicians. The currently developing inter-specialty collaboration should be hailed as a positive change. It promises to clarify the target-based terminology for RAIT. It defines RAIT of post total thyroidectomy (PTT), presumably benign thyroid as 'remnant ablation' (RA). 'Adjuvant treatment' (AT) referrers to RAIT of suspected microscopic DTC that is inherently occult on diagnostic imaging. RAIT directed at DTC lesion(s) overtly seen on diagnostic imaging is termed 'treatment of known disease' (TKD). It was recently recognized that a 'recurrent' DTC is actually occult residual DTC in the majority of cases. Thyroglobulin with remnant uptake concord (TRUC) method (aka Tulchinsky method) was developed to validate that a benign remnant in the post-thyroidectomy neck bed, as quantified by the RAI uptake, is concordant with a measured thyroglobulin (Tg) level at the time of the initial post-thyroidectomy evaluation. It allows recognition of occult residual DTC contribution to post-thyroidectomy Tg. Case examples demonstrate the application of the TRUC method for a logical selection of a specific RAIT category, using imaging-guided identification and management of RAI-avid versus RAI-nonavid residual DTC, i.e. the radiotheragnostics paradigm.

Intravenous Line Phase-Wrap Artifact at Bilateral Axial 3-T Breast MRI: Identification, Analysis, and Solution.

Purpose: To understand and remove the source of a phase-wrap artifact produced by residual contrast agent in the intravenous line during acquisition of bilateral axial 3-T dynamic contrast material-enhanced (DCE) breast MRI. Materials and Methods: A two-part study involved a phantom experiment, followed by an institutional review board approved clinical intervention, to evaluate the phase-wrap artifact at MRI. A phantom model evaluated artifact production by using an intravenous line filled with fluids with varying concentrations of gadolinium-based contrast agent (0, 0.4, 0.8, 1.2, 1.6, and 2 mmol/mL) and by positioning the simulated intravenous line within several fields of view (FOV) at 3-T MRI in breast coils. Next, a clinical assessment was performed with a total of 400 patients (control group:interventional group, 200:200) to determine the effect of taping the intravenous line to the patients' backs. Breast MR images were assessed blindly for the presence of the artifact. Software was used for statistical analysis with a P value of less than .05 considered a significant difference. Results: In the phantom model, the artifact was produced only with a 0.4 mmol/mL gadolinium concentration and when the tubing was either close to the edge or within a FOV of 350-450 mm. In the clinical experiment, the artifact was more prevalent in the retrospective control group than in the prospective intervention group (52.5% [105 of 200] vs 22% [44 of 200]; P < .005). Conclusion: The presence of phase-wrap artifacts can be reduced by moving the contrast agent intravenous line out of the FOV during acquisition by taping it to a patient's back during bilateral axial 3-T DCE breast MRI.Keywords: Breast, MR-Imaging, Phantom Studies© RSNA, 2020.

Cardiac MRI: A Useful Tool for Differentiating Cardiac Thrombi from Tumors.

BACKGROUND: Correct diagnosis of cardiac masses is a challenge in clinical practice. Accurate identification and differentiation between cardiac thrombi and tumors is crucial because prognosis and appropriate clinical management vary substantially. OBJECTIVES: To evaluate the diagnostic performances of cardiac magnetic resonance imaging (CMR) in differentiating between cardiac thrombi and tumors. METHODS: A retrospective review of a prospectively maintained database of all CMR scans was performed to distinguish between cardiac thrombi and tumors during a 10 year period in a single academic referral center (2004-2013). Cases with an available standard of reference for a definite diagnosis were included. Correlation of CMR differentiation between thrombi and tumors with an available standard of reference was performed. Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy were reported. RESULTS: In this study, 101 consecutive patients underwent CMR for suspicious cardiac masses documented on transthoracic or transesophageal echocardiography. CMR did not detect any cardiac pathology in 17% (17/101), including detection of anatomical variants and benign findings in 18% (15/84). Of the remaining 69 patients, CMR diagnosis was correlated with histopathologic result in 74% (51/69), imaging follow-up in 22% (15/69), and a definite CMR diagnosis (lipoma) in 4% (3/69). For tumors, diagnostic accuracy, sensitivity, specificity, PPV, and NPV were 96.6%, 98%, 86.6%, 96.2%, and 96.6%, respectively. For thrombi, the results were 93.6%, 86.7%, 98.04%, 92.9%, and 97%, respectively. CONCLUSIONS: CMR is highly accurate in differentiating cardiac thrombi from tumors and should be included in the routine evaluation of cardiac masses.

Radiation Reduction in Low Dose Pulsed Fluoroscopy versus Standard Dose Continuous Fluoroscopy during Fluoroscopically-Guided Lumbar Punctures: A Prospective Controlled Study.

PURPOSE: The purpose of this study was to evaluate radiation dose reduction in fluoroscopically guided lumbar punctures (FGLP) using "pulsed fluoroscopy in a low dose mode" compared with the commonly used "continuous fluoroscopy in a standard dose mode" while maintaining the technical success. MATERIALS AND METHODS: Thirty-five consecutive patients who underwent FGLP divided randomly to seventeen patients in the control group with standard dose continuous FGLP and eighteen patients in the study group with low-dose low-frame-rate of 3 frames per second (fps) FGLP. Entrance surface dose measurements from a dosimeter device were recorded as well as the dose area product (DAP). RESULTS: A total of 35 patients with average age of 52 years (range: 15-87 [±17 standard deviation [SD]]) were evaluated. Average entrance surface dose of the study group was significantly lower (3.81 mGy [range: 0.21-11.14, [±2.8 SD]]) compared with the control group (22.45 mGy [range: 1.23-73.44, [±19.41 [SD]]). The average DAP of the study group (10 mGy·cm2 [range: 1-41, [±9.8 SD]]) was also significantly lower than the control group (65 mGy·cm2 [range: 5-199, [±53 SD]]). Success rate was similar between the study and control groups. CONCLUSION: Low dose pulsed fluoroscopy of 3 fps significantly reduces radiation exposure by about 600% compared with standard dose continuous fluoroscopy in FGLP. Utilizing this radiation saving strategy will allow to dramatically reduce radiation exposure, without impacting the technical success rate.

Degenerative changes of the thoracic spine do exist in patients with diffuse idiopathic skeletal hyperostosis: a detailed thoracic spine CT analysis.

Background Degenerative intervertebral disease (DID) is an exclusion criterion in the Resnick and Niwayama radiographic classification for diffuse idiopathic skeletal hyperostosis (DISH). However, although DID was previously described in DISH, no systematic computed tomography (CT) analysis has been reported so far. Purpose To assess for the presence and prevalence of such changes on CT examinations of the thoracic spine of individuals with DISH. Material and Methods Intervertebral space (D1-L1) on chest CT examinations of DISH patients was retrospectively evaluated for the presence of DID. Parameters evaluated were disc space height, disc protrusion, subchondral cysts/sclerosis, Schmorl nodes, vacuum phenomenon, and posterior elements including costovertebral and facet joints. Parameters were compared with two age- and gender-matched control groups of individuals whose entire spine CT lacked evidence of DISH (Control 1 individuals < 2 flowing osteophytes, Control 2 individuals < 4 and ≥ 2 flowing osteophytes). Results A total of 158 participants (DISH/Control 1/Control 2 = 54/54/50; 106 men, 52 women; average age = 70.6 years) were evaluated. Average intervertebral disc height was significantly lower in the DISH group compared with both control groups (DISH/Control 1/Control 2 = 4.55/5.13/5.01 mm, P < 0.001). Costovertebral degenerative changes were more prevalent in DISH patients ( P < 0.05) and, except for vacuum phenomenon (more prevalent in controls), other DID changes were as prevalent in DISH as in controls. Conclusion The presence of degenerative intervertebral changes on thoracic CT should not deter from diagnosing DISH. Thus, the radiographic Resnick and Niwayama DISH criteria cannot be directly adapted to CT.

Gynecological Lymphoma: A Case Series and Review of the Literature.

OBJECTIVE: The aim of the study was to evaluate the radiological characteristics of gynecological lymphoproliferative disease (LPD) and specific imaging features that may suggest the diagnosis. METHODS: Two readers conducted a retrospective evaluation of imaging studies of 13 female patients presenting with a gynecological LPD. A literature review was also performed. RESULTS: Of the 13 evaluated women, 9 had ovarian involvement, 3 had cervical involvement, and 1 had uterine involvement. The most common lesion characteristics were homogenous masses (11), with mild contrast enhancement (9), followed by soft-tissue necrosis (4), prominent blood vessels displaced by the lesions (4), linear arrangement of cysts at the periphery of the ovaries (3), and "touching" ovaries in all cases of bilateral ovarian involvement. CONCLUSIONS: A solid large homogeneous mass with mild contrast enhancement should alert the radiologist to the possibility of the differential diagnosis of LPD. Radiologists should be "the gatekeepers" by raising this possibility to avoid unnecessary surgery and enable appropriate treatment.

Metal-on-Metal Hip Replacement: MRI Signal Intensities of Different Body Tissues and Their Relations to Blood Metal Ion Levels.

BACKGROUND: Metal-on-metal total hip prostheses (MoM-THR) have been shown to produce hypersensitivity reactions and fluid collection (pseudotumor) by the hip as well as high blood metal ions levels (BMILs). OBJECTIVES: To evaluate the magnetic resonance imaging (MRI) signal-to-noise ratio (S/N) in selected body tissues around the hip of patients who underwent MoM hip replacement and to correlate to BMILs. METHODS: Sixty-one MRI hip examinations in 54 post-MoM-THR patients (18 males, 36 females, mean age 65 years) were retrospectively evaluated independently by two readers. The mean S/N ratio in a region of interest was calculated for periprosthetic pseudotumor collection (PPC), the bladder, fat, and muscle on axial T1w, FSE-T2w, and short tau inversion recovery (STIR) sequences on the same location. BMILs were retrieved from patient files. RESULTS: PPC was detected in 32 patients (52%) with an average volume of 82.48 mm3. BMIL did not correlate with the presence of PPCs but positively correlated with the PPC's volume. A trend for positive correlation was found between BMILs and S/N levels of STIR images for muscle and bladder as well as for PPC and cobalt levels. A trend for correlation was also seen between BMIL with PPC's T1 w S/N. CONCLUSIONS: Alteration of MRI S/N for different hip tissues showed a tendency for correlation with BMILs, possibly suggesting that metal deposition occurs in the PPC as well as in the surrounding tissues and bladder.

CT Abnormalities in the Sacroiliac Joints of Patients With Diffuse Idiopathic Skeletal Hyperostosis.

OBJECTIVE: The purpose of this study is to characterize sacroiliac joints (SIJs) findings at CT of patients with diffuse idiopathic skeletal hyperostosis (DISH), a condition characterized (using the Resnick classification criteria) by ossification of at least four contiguous vertebrae in the thoracic spine and preserved disk space, but without radiographic evidence of intraarticular SIJ abnormalities. MATERIALS AND METHODS: Pelvic CT examinations of 104 patients with DISH (fulfilling the Resnick criteria on spinal CT) and 106 age- and sex-matched control subjects whose entire spine lacked CT evidence of DISH (total, 149 men and 61 women; mean [± SD] age, 72.3 ± 8.7 years) were retrospectively evaluated for the presence of intra- and extraarticular bridging osteophytes, spurs, subchondral cystlike changes, erosions, and sclerosis of SIJs. Excluded were patients with known ankylosing spondylitis or inflammatory-related diseases. Data were analyzed using multivariate ANOVA to examine the degree of difference between patients with DISH and control subjects. Logistic regression analysis was used to generate odds ratios to examine their discriminatory ability. ROC analysis was then applied to examine the sensitivity and specificity of the results. RESULTS: The frequency of anterior bridging, posterior bridging, entheseal bridging, and joint ankylosis was significantly higher among patients with DISH compared with control subjects (48% vs 9%, 20% vs 1%, 34% vs 4%, and 23% vs 0%, respectively; p < 0.001 for all comparisons). CONCLUSION: Intraarticular ankylosis seen at CT, an entity not included in the Resnick classification criteria, is common among patients with DISH, which implies that the radiologic classification criteria for DISH need to be revised.

Bilateral total hip replacement: periprosthetic pseudotumor collections are more prevalent in metal-on-metal implants compared to non-metal-on-metal ones.

BACKGROUND: Metal-on-metal (MoM) hip prostheses were shown to have high failure rates including the formation of periprosthetic cystic masses called periprosthetic pseudotumor collections (PPCs). PURPOSE: To compare MRI prevalence and size of PPCs in patients after bilateral total-hip-replacement (THR) in which at least one hip was replaced by a MoM prosthesis. MATERIAL AND METHODS: All sequential MRI examinations of patients with bilateral THR in which at least one is MoM (2010-2013) were retrospectively evaluated. MRIs were analyzed separately by two readers for the presence and size of PPCs. These were compared between MoM and non-MoM implants and between patients with unilateral or bilateral-MoM prostheses. Blood metal ion levels were also compared. RESULTS: Seventy hips of 35 patients (male:female ratio, 9:26; mean age, 64 years; age range, 35-82 years) were assessed. Sixteen patients (45%) underwent bilateral MoM-THRs and 19 (55%) had one MoM and the other non-MoM, yielding 51 MoM THRs and 19 non-MoM THRs. Twenty-eight PPCs were detected in 19 patients (54%): 26 in MoM THRs (51%) and two in non-MoM THRs (10.5%, P = 0.00009). The mean PPC volume in the MoM implants (107 mm(3)) was higher than that of the non-MoM implants (18 mm(3), P = 0.49). Cobalt/chromium blood levels were 78 µg/L/25 µg/L for bilateral MoM THRs and 21 µg/L/10 µg/L for unilateral MoM implants (P = 0.1 and 0.16, respectively). CONCLUSION: PPCs are more prevalent in MoM THRs compared to non-MoM THRs. Larger PPC volumes and higher blood metal ion levels were detected in patients with bilateral MoM THRs compared to unilateral MoM THRs (P > 0.05).

JOURNAL CLUB: Is screening MRI indicated for women with a personal history of breast cancer? Analysis based on biopsy results.

OBJECTIVE: American College of Radiology and Society of Breast Imaging guidelines call for routine breast MRI screening only for women with the highest risk profiles for development of breast cancer, suggesting that screening of women at lower risk might result in an increased frequency of false-positive biopsy results. The purpose of this study was to test this assumption by comparing MRI-guided biopsy outcomes of lesions detected at MRI screening of women with a personal history of breast cancer with outcomes among women with genetic or familial high risk. MATERIALS AND METHODS: Outcomes of 130 MRI-guided biopsies were analyzed. One group consisted of women with hereditary (genetic or familial) risk, and the other group consisted of women with a personal history of breast cancer. Biopsies were performed with a 9-gauge vacuum-assisted device or surgically after MRI localization. RESULTS: Of 130 MRI-guided biopsies, 20 (15%) yielded malignant histologic findings, 14 (11%) yielded high-risk lesions, and 96 (74%) had benign findings. There was a slightly higher malignancy rate for the personal-risk group (19%) compared with the hereditary-risk group (13.5%). There also was a slightly higher combined rate of malignancy and high-risk lesions (34% vs 22%) with no statistically significant difference (p < 0.25, p < 0.12). Patients in the hereditary-risk group were younger (44 ± 1.2 vs 54 ± 1.7 years; p < 0.001) than those in the personal-risk group. CONCLUSION: Our preliminary data show no difference between the two risk groups with respect to probability of an MRI-guided biopsy result of malignancy, calling into question the proposed assumption. Further prospective studies of the role of MRI screening combined with MRI-guided biopsy when required for patients with previously treated localized breast cancer may be indicated.