Utility of 18F-fluorodeoxyglucose positron emission tomography in presurgical evaluation of patients with epilepsy: A multicenter study.

OBJECTIVE: 18F-Fluorodeoxyglucose positron emission tomography (FDG-PET) is widely used in presurgical assessment in patients with drug-resistant focal epilepsy (DRE) if magnetic resonance imaging (MRI) and scalp electroencephalography (EEG) do not localize the seizure onset zone or are discordant. METHODS: In this multicenter, retrospective observational cohort study, we included consecutive patients with DRE who had undergone FDG-PET as part of their presurgical workup. We assessed the utility of FDG-PET, which was defined as contributing to the decision-making process to refer for resection or intracranial EEG (iEEG) or to conclude surgery was not feasible. RESULTS: We included 951 patients in this study; 479 had temporal lobe epilepsy (TLE), 219 extratemporal epilepsy (ETLE), and 253 epilepsy of uncertain lobar origin. FDG-PET showed a distinct hypometabolism in 62% and was concordant with ictal EEG in 74% in TLE and in 56% in ETLE (p < .001). FDG-PET was useful in presurgical decision-making in 396 patients (47%) and most beneficial in TLE compared to ETLE (58% vs. 44%, p = .001). Overall, FDG-PET contributed to recommending resection in 78 cases (20%) and iEEG in 187 cases (47%); in 131 patients (33%), FDG-PET resulted in a conclusion that resection was not feasible. In TLE, seizure-freedom 1 year after surgery did not differ significantly (p = .48) between patients with negative MRI and EEG-PET concordance (n = 30, 65%) and those with positive MRI and concordant EEG (n = 46, 68%). In ETLE, half of patients with negative MRI and EEG-PET concordance and three quarters with positive MRI and concordant EEG were seizure-free postsurgery (n = 5 vs. n = 6, p = .28). SIGNIFICANCE: This is the largest reported cohort of patients with DRE who received presurgical FDG-PET, showing that FDG-PET is a useful diagnostic tool. MRI-negative and MRI-positive cases with concordant FDG-PET results (with either EEG or MRI) had a comparable outcome after surgery. These findings confirm the significance of FDG-PET in presurgical epilepsy diagnostics.

Predictors of survival and time to progression following operative management of intramedullary spinal cord astrocytomas.

PURPOSE: Surgical resection is considered standard of care for primary intramedullary astrocytomas, but the infiltrative nature of these lesions often precludes complete resection without causing new post-operative neurologic deficits. Radiotherapy and chemotherapy serve as potential adjuvants, but high-quality data evaluating their efficacy are limited. Here we analyze the experience at a single comprehensive cancer center to identify independent predictors of postoperative overall and progression-free survival. METHODS: Data was collected on patient demographics, tumor characteristics, pre-operative presentation, resection extent, long-term survival, and tumor progression/recurrence. Kaplan-Meier curves modeled overall and progression-free survival. Univariable and multivariable accelerated failure time regressions were used to compute time ratios (TR) to determine predictors of survival. RESULTS: 94 patients were included, of which 58 (62%) were alive at last follow-up. On multivariable analysis, older age (TR = 0.98; p = 0.03), higher tumor grade (TR = 0.12; p < 0.01), preoperative back pain (TR = 0.45; p < 0.01), biopsy [vs GTR] (TR = 0.18; p = 0.02), and chemotherapy (TR = 0.34; p = 0.02) were significantly associated with poorer survival. Higher tumor grade (TR = 0.34; p = 0.02) and preoperative bowel dysfunction (TR = 0.31; p = 0.02) were significant predictors of shorter time to detection of tumor growth. CONCLUSION: Tumor grade and chemotherapy were associated with poorer survival and progression-free survival. Chemotherapy regimens were highly heterogeneous, and randomized trials are needed to determine if any optimal regimens exist. Additionally, GTR was associated with improved survival, and patients should be counseled about the benefits and risks of resection extent.

High resolution 3D magnetic resonance imaging of Gruber's ligament: a pilot study.

INTRODUCTION: Gruber's ligament (GL), a surgical landmark, extends from the lateral upper clivus to the petrous apex (PA), forming the superior boundary of Dorello's canal (DC). It overlies the interdural segment of the abducens nerve (CN VI). High-resolution 3D skull base MRI (SB-MRI) demonstrates anatomic details visible to the surgeon, but not well seen on traditional cross-sectional imaging. The aim of this study was to demonstrate visualization of the GL and its relationship to CN VI utilizing contrast enhanced high-resolution SB-MRI. METHODS: Two neuroradiologists retrospectively reviewed in consensus the SB-MRIs of 27 skull base sides, among 14 patients. GL detection rate, confidence of detection, and GL length were recorded. When GL was successfully identified, the position of the interdural segment of CN VI within DC was recorded. RESULTS: GL was readily identified in 16 skull base sides (59%), identified with some difficulty in 2 skull base sides (7%), and failed to be identified in 9 skull base sides (33%). The mean GL length was 7.1 mm (4.5-9.3 mm). Among the 18 cases where GL was successfully identified, CN VI was readily identified in all cases (100%), coursing the lateral third of DC in 72% of sides, and middle third in the remaining 28% of sides. CONCLUSION: GL can be identified in approximately two-thirds of cases utilizing 3D high resolution SB-MRI. CN VI passes most commonly along the lateral third of DC. This is the first report demonstrating visualization of GL and its relation to CN VI, on imaging.

Segmental Imaging of the Trochlear Nerve: Anatomic and Pathologic Considerations.

BACKGROUND: The trochlear nerve (the fourth cranial nerve) is the only cranial nerve that arises from the dorsal aspect of the midbrain. The nerve has a lengthy course making it highly susceptible to injury. It is also the smallest cranial nerve and is often difficult to identify on neuroimaging. EVIDENCE ACQUISITION: High-resolution 3-dimensional skull base MRI allows for submillimeter isotropic acquisition and is optimal for cranial nerve evaluation. In this text, the detailed anatomy of the fourth cranial nerve applicable to imaging will be reviewed. RESULTS: Detailed anatomic knowledge of each segment of the trochlear nerve is necessary in patients with trochlear nerve palsy. A systematic approach to identification and assessment of each trochlear nerve segment is essential. Pathologic cases are provided for each segment. CONCLUSIONS: A segmental approach to high-resolution 3-dimensional MRI for the study of the trochlear nerve is suggested.

Nonepithelial Tumors of the Larynx: Single-Institution 13-Year Review with Radiologic-Pathologic Correlation.

Nonepithelial tumors of the larynx are rare and represent a minority of all laryngeal neoplasms. Imaging has an important role in the diagnosis, treatment planning, and surveillance of these entities. However, unfamiliarity with these neoplasms can cause diagnostic difficulties for radiologists, especially because many of the imaging findings are nonspecific. By using a systematic approach based on clinical history, patient age and gender, lesion location, endoscopic results, and specific imaging findings, the differential diagnosis can often be narrowed. These tumors typically affect the submucosal layer, so if a tumor has an intact mucosa at endoscopy, a nonepithelial neoplasm is the most likely diagnosis. Nonepithelial tumors of the larynx can arise from the laryngeal cartilage or muscle or from the surrounding lymphoid tissue or blood vessels. Consequently, imaging findings typically correspond to the specific cell type from which it originated. Recognizing specific features (eg, metaplastic bone formation, macroscopic fat, or enhancement pattern) can often help narrow the differential diagnosis. In addition, identification of noncircumscribed borders of the lesion and invasion of the adjacent structures is key to diagnosis of a malignant process rather than a benign neoplasm. Understanding the pathologic correlation is fundamental to understanding the radiologic manifestations and is ultimately crucial for differentiation of nonepithelial laryngeal neoplasms. Online supplemental material is available for this article. ©RSNA, 2020.

Joubert syndrome: neuroimaging findings in 110 patients in correlation with cognitive function and genetic cause.

BACKGROUND: Joubert syndrome is a clinically and genetically heterogeneous ciliopathy. Neuroimaging findings have not been systematically evaluated in a large cohort of patients with Joubert syndrome in correlation with molecular genetic cause and cognitive function. METHODS: Brain MRI of 110 patients with Joubert syndrome was included in this study. A comprehensive evaluation of brain MRI studies for infratentorial and supratentorial morphological abnormalities was performed. Genetic cause was identified by whole-exome sequencing, and cognitive functions were assessed with age-appropriate neurocognitive tests in a subset of patients. RESULTS: The cerebellar hemispheres were enlarged in 18% of the patients, mimicking macrocerebellum. The posterior fossa was enlarged in 42% of the patients, resembling Dandy-Walker malformation. Abnormalities of the brainstem, such as protuberance at the ventral contour of the midbrain, were present in 66% of the patients. Abnormalities of the supratentorial brain were present in approximately one-third of the patients, most commonly malrotation of the hippocampi. Mild ventriculomegaly, which typically did not require shunting, was present in 23% of the patients. No correlation between neuroimaging findings and molecular genetic cause was apparent. A novel predictor of outcome was identified; the more severe the degree of vermis hypoplasia, the worse the neurodevelopmental outcome was. CONCLUSIONS: The spectrum of neuroimaging findings in Joubert syndrome is wide. Neuroimaging does not predict the genetic cause, but may predict the neurodevelopmental outcome. A high degree of vermis hypoplasia correlates with worse neurodevelopmental outcome. This finding is important for prognostic counselling in Joubert syndrome.

Visualization of the Oropharynx With Transcervical Ultrasound.

OBJECTIVE: The purposes of this article are to illustrate the sonographic appearance of the oropharynx and to discuss the potential role of ultrasound in evaluation of the oropharynx. CONCLUSION: Ultrasound is not currently used in the standard clinical evaluation of the oropharynx, but it is a promising imaging modality for evaluating the base of the tongue and the palatine tonsils. Ultrasound is comparable and complementary to CT and MRI, which have recognized limitations.

High-Resolution 3D Magnetic Resonance Imaging of the Sixth Cranial Nerve: Anatomic and Pathologic Considerations by Segment.

BACKGROUND: Weakness of the sixth cranial nerve is the most common cause of an ocular motor cranial nerve palsy. It is often difficult to identify a corresponding abnormality on neuroimaging to correlate with the clinical examination. EVIDENCE ACQUISITION: High-resolution 3D skull base magnetic resonance imaging (MRI) allows for visualization of the sixth nerve along much of its course and may increase sensitivity for abnormalities in regions that previously were challenging to evaluate. In this review, the authors share their experience with high-resolution imaging of the sixth nerve. RESULTS: For each segment, anatomic features visible on high-resolution imaging are described along with relevant pathologic entities. CONCLUSIONS: We present a segmental approach to high-resolution 3D MRI for evaluation of the sixth nerve from the nuclear to the orbital segment.

The role of imaging in the management of progressive glioblastoma : a systematic review and evidence-based clinical practice guideline.

QUESTION: Which imaging techniques most accurately differentiate true tumor progression from pseudo-progression or treatment related changes in patients with previously diagnosed glioblastoma? TARGET POPULATION: These recommendations apply to adults with previously diagnosed glioblastoma who are suspected of experiencing progression of the neoplastic process. RECOMMENDATIONS LEVEL II: Magnetic resonance imaging with and without gadolinium enhancement is recommended as the imaging surveillance method to detect the progression of previously diagnosed glioblastoma. LEVEL II: Magnetic resonance spectroscopy is recommended as a diagnostic method to differentiate true tumor progression from treatment-related imaging changes or pseudo-progression in patients with suspected progressive glioblastoma. LEVEL III: The routine use of positron emission tomography to identify progression of glioblastoma is not recommended. LEVEL III: Single-photon emission computed tomography imaging is recommended as a diagnostic method to differentiate true tumor progression from treatment-related imaging changes or pseudo-progression in patients with suspected progressive glioblastoma.

The evaluation of FDG-PET imaging for epileptogenic focus localization in patients with MRI positive and MRI negative temporal lobe epilepsy.

INTRODUCTION: We studied the contribution of interictal FDG-PET ([18 F] fluorodeoxyglucose-positron emission tomography) in epileptic focus identification in temporal lobe epilepsy patients with positive, equivocal and negative magnetic resonance imaging (MRI). METHODS: Ninety-eight patients who underwent surgical treatment for drug resistant temporal lobe epilepsy after neuropsychological evaluation, scalp video EEG monitoring, FDG-PET, MRI and/or long-term intracranial EEG and with >12 months clinical follow-up were included in this study. FDG-PET findings were compared to MRI, histopathology, scalp video EEG and long-term intracranial EEG monitoring. RESULTS: FDG-PET lateralized the seizure focus in 95 % of MRI positive, 69 % of MRI equivocal and 84 % of MRI negative patients. There was no statistically significant difference between the surgical outcomes among the groups with Engel class I and II outcomes achieved in 86 %, 86 %, 84 % of MRI positive, equivocal and negative temporal lobe epilepsy patients, respectively. The patients with positive unilateral FDG-PET demonstrated excellent postsurgical outcomes, with 96 % Engel class I and II. Histopathology revealed focal lesions in 75 % of MRI equivocal, 84 % of MRI positive, and 23 % of MRI negative temporal lobe epilepsy cases. CONCLUSION: FDG-PET is an accurate noninvasive method in lateralizing the epileptogenic focus in temporal lobe epilepsy, especially in patients with normal or equivocal MRIs, or non-lateralized EEG monitoring. Very subtle findings in MRI are often associated with histopathological lesions and should be described in MRI reports. The patients with negative or equivocal MRI temporal lobe epilepsy are good surgical candidates with comparable postsurgical outcomes to patients with MRI positive temporal lobe epilepsy.

Axial 3D gradient-echo imaging for improved multiple sclerosis lesion detection in the cervical spinal cord at 3T.

INTRODUCTION: In multiple sclerosis (MS), spinal cord imaging can help in diagnosis and follow-up evaluation. However, spinal cord magnetic resonance imaging (MRI) is technically challenging, and image quality, particularly in the axial plane, is typically poor compared to brain MRI. Because gradient-recalled echo (GRE) images might offer improved contrast resolution within the spinal cord at high magnetic field strength, both without and with a magnetization transfer prepulse, we compared them to T2-weighted fast-spin-echo (T2-FSE) images for the detection of MS lesions in the cervical cord at 3T. METHODS: On a clinical 3T MRI scanner, we studied 62 MS cases and 19 healthy volunteers. Axial 3D GRE sequences were performed without and with off-resonance radiofrequency irradiation. To mimic clinical practice, all images were evaluated in conjunction with linked images from a sagittal short tau inversion recovery scan, which is considered the gold standard for lesion detection in MS. Two experienced observers recorded image quality, location and size of focal lesions, atrophy, swelling, and diffuse signal abnormality independently at first and then in consensus. RESULTS: The number and volume of lesions detected with high confidence was more than three times as high on both GRE sequences compared to T2-FSE (p < 0.0001). Approximately 5 % of GRE scans were affected by artifacts that interfered with image interpretation, not significantly different from T2W-FSE. CONCLUSIONS: Axial 3D GRE sequences are useful for MS lesion detection when compared to 2D T2-FSE sequences in the cervical spinal cord at 3T and should be considered when examining intramedullary spinal cord lesions.

Feasibility of clinical evaluation of individuals with increased risk for HPV-associated oropharynx cancer.

BACKGROUND: Human papillomavirus-associated oropharynx squamous cell carcinoma (HPV-OPSCC) has no known pre-malignant lesion. While vaccination offers future primary prevention, there is current interest in secondary prevention. The feasibility of clinical evaluation of individuals at increased risk for HPV-OPSCC is unclear. METHODS: Individuals with risk factors for HPV-OPSCC were enrolled in a prospective study (MOUTH). Participants positive for biomarkers associated with HPV-OPSCC were eligible for a clinical evaluation which comprised a head and neck examination and imaging with ultrasound and/or magnetic resonance imaging (MRI). This study was designed to evaluate feasibility of clinical evaluation in a screening study. RESULTS: Three hundred and eighty-four participants were eligible for clinical evaluation. Of the 384, 204 (53%) completed a head and neck examination or imaging. Of these, 66 (32%) completed MRI (n = 51) and/or ultrasound (n = 64) studies. CONCLUSIONS: Clinical evaluations, including head and neck examination and imaging, are feasible in the context of a screening study for HPV-OPSCC.

Clinical and radiologic features of fungal diseases of the paranasal sinuses.

OBJECTIVE: To document the clinical and imaging characteristics of fungal rhinosinusitis (FRS). METHODS: Imaging studies of 28 patients with FRS were retrospectively analyzed, considering the type of fungal disease, location, signal characteristics, bone changes, expansion, and extrasinus extension. RESULTS: Acute invasive FRS showed unilateral pacifications of the sinonasal cavity, perisinus fat infiltration and/or bone destruction. Chronic invasive FRS demonstrated masslike hyperattenuating soft tissue, with bony destruction. The soft tissue changes were hypointense on T1 and markedly hypointense on T2-weighted images. In allergic FRS, hyperattenuating soft tissue causing paranasal expansion due to allergic mucin was observed on CT. Fungus ball presented as a hyperattenuating lesion with calcifications within a single sinus. CONCLUSION: The radiological features of each type of FRS are distinctive and should afford a specific diagnosis in the proper clinical setting.

Inner ear anomalies seen on CT images in people with Down syndrome.

BACKGROUND: Although dysplasia of inner ear structures in Down syndrome has been reported in several histopathological studies, the imaging findings have not been widely studied. OBJECTIVE: To evaluate the prevalence and clinical significance of inner ear anomalies detected on CT images in patients with Down syndrome. MATERIALS AND METHODS: The temporal bone CT images of patients with Down syndrome were assessed for inner ear anomalies; clinical notes and audiograms were reviewed for hearing loss. Logistic regression models were employed to identify which CT findings were associated with sensorineural hearing loss (SNHL). RESULTS: Inner ear anomalies were observed in 74.5% (38/51) of patients. Malformed bone islands of lateral semicircular canal (LSCC), narrow internal auditory canals (IACs), cochlear nerve canal stenoses, semicircular canal dehiscence (SCCD), and enlarged vestibular aqueducts were detected in 52.5% (53/101), 24.5% (25/102), 21.4% (21/98), 8.8% (9/102) and 2% (2/101) of patients' ears, respectively. IAC stenosis had the highest odds ratio (OR = 5.37, 95% CI: 1.0-28.9, P = 0.05) for SNHL. CONCLUSION: Inner ear anomalies occurred in 74.5% of our population, with malformed (<3 mm) bone island of LSCC being the most common (52.5%) anomaly. Narrow IAC was seen in 24.5% of patients with Down syndrome and in 57.1% of ears with SNHL. High-resolution CT is a valuable for assessing the cause of hearing loss in people with Down syndrome.

Imaging of the Postoperative Skull Base and Cerebellopontine Angle.

For pathologic conditions affecting the skull base and cerebellopontine angle, imaging techniques have advanced to assess for residual disease, disease progression, and postoperative complications. Knowledge regarding various surgical approaches of skull base tumor resection, expected postoperative appearance, and common postsurgical complications guides radiologic interpretation. Complexity of skull base anatomy, small size of the relevant structures, lack of familiarity with surgical techniques, and postsurgical changes confound radiologic evaluation. This article discusses the imaging techniques, surgical approaches, expected postoperative changes, and complications after surgery of the skull base, with emphasis on the cerebellopontine angle, anterior cranial fossa, and central skull base regions.

Model-based pulse pileup and charge sharing compensation for photon counting detectors: A simulation study.

PURPOSE: We aim at developing a model-based algorithm that compensates for the effect of both pulse pileup (PP) and charge sharing (CS) and evaluates the performance using computer simulations. METHODS: The proposed PCP algorithm for PP and CS compensation uses cascaded models for CS and PP we previously developed, maximizes Poisson log-likelihood, and uses an efficient three-step exhaustive search. For comparison, we also developed an LCP algorithm that combines models for a loss of counts (LCs) and CS. Two types of computer simulations, slab- and computed tomography (CT)-based, were performed to assess the performance of both PCP and LCP with 200 and 800 mA, (300 µm)2  × 1.6-mm cadmium telluride detector, and a dead-time of 23 ns. A slab-based assessment used a pair of adipose and iodine with different thicknesses, attenuated X-rays, and assessed the bias and noise of the outputs from one detector pixel; a CT-based assessment simulated a chest/cardiac scan and a head-and-neck scan using 3D phantom and noisy cone-beam projections. RESULTS: With the slab simulation, the PCP had little or no biases when the expected counts were sufficiently large, even though a probability of count loss (PCL) due to dead-time loss or PP was as high as 0.8. In contrast, the LCP had significant biases (>±2 cm of adipose) when the PCL was higher than 0.15. Biases were present with both PCP and LCP when the expected counts were less than 10-120 per datum, which was attributed to the fact that the maximum likelihood did not approach the asymptote. The noise of PCP was within 8% from the Cramér-Rao lower bounds for most cases when no significant bias was present. The two CT studies essentially agreed with the slab simulation study. PCP had little or no biases in the estimated basis line integrals, reconstructed basis density maps, and synthesized monoenergetic CT images. But the LCP had significant biases in basis line integrals when X-ray beams passed through lungs and near the body and neck contours, where the PCLs were above 0.15. As a consequence, basis density maps and monoenergetic CT images obtained by LCP had biases throughout the imaged space. CONCLUSION: We have developed the PCP algorithm that uses the PP-CS model. When the expected counts are more than 10-120 per datum, the PCP algorithm is statistically efficient and successfully compensates for the effect of the spectral distortion due to both PP and CS providing little or no biases in basis line integrals, basis density maps, and monoenergetic CT images regardless of count-rates. In contrast, the LCP algorithm, which models an LC due to pileup, produces severe biases when incident count-rates are high and the PCL is 0.15 or higher.

Predictive Factors for Concurrent Tegmen Dehiscence in Superior Canal Dehiscence Syndrome.

OBJECTIVES: To describe factors predictive of tegmen dehiscence in subjects with superior semicircular canal dehiscence syndrome (SCDS). STUDY DESIGN: Retrospective case series. SETTING: Tertiary referral center. PATIENTS: Subjects with SCDS who underwent middle fossa craniotomy (MFC) for plugging/resurfacing. MAIN OUTCOME MEASURES: Operative and radiographic findings of tegmen dehiscences, preoperative low frequency air-bone gaps (LF-ABGs), ocular vestibular evoked myogenic potential (oVEMP) amplitudes, size of superior semicircular canal dehiscence (SCD), and history of obesity or obstructive sleep apnea (OSA). RESULTS: One hundred thirty six patients (avg. age, 50.6 yr, 55.1% female) underwent MFC for repair of SCDS. Tegmen dehiscences were commonly found intraoperatively (tegmen tympani dehiscence [TTD] in 19.9% [11% with dural contact of ossicles], tegmen mastoideum dehiscence [TMD] in 28.7%). There were no differences in preoperative LF-ABGs and preoperative oVEMP amplitudes with respect to tegmen status. The sensitivity and specificity of computed tomography (CT) for predicting an intraoperatively confirmed TTD was 85 and 74%, respectively, and 44 and 79% for TMD. History of obesity and OSA did not differ between those with and without tegmen dehiscences. The presence of contralateral SCD and increasing cross-sectional area of SCD were both significantly associated with concurrent tegmen defects. CONCLUSIONS: Obesity, OSA, preoperative oVEMP, and LF-ABG do not differ between those with SCD alone and those with SCD and concurrent tegmen dehiscences. Likewise, CT scans have relatively low sensitivity for identifying tegmen dehiscences. The presence of concurrent tegmen defects is more common in subjects with larger SCD cross-sectional areas and contralateral SCD.

Predictors of Free Flap Volume Loss in Nonosseous Reconstruction of Head and Neck Oncologic Defects.

OBJECTIVES: Free tissue reconstruction of the head and neck must be initially overcorrected due to expected postoperative free flap volume loss, which can be accelerated by adjuvant radiation therapy. In this study, we aim to identify patient and treatment-specific factors that may significantly contribute to this phenomenon and translate these characteristics into a predictive model for expected percent free flap volume loss in a given patient. METHODS: Patients with a history of oral cavity and/or oropharyngeal cancer who underwent nonosseous free flap reconstruction were reviewed between January 2009 and November 2018 at a tertiary care center. Demographics/characteristics, total radiation dose, radiation fractionation (RF), and pre/postradiation free flap volume as evaluated by computed tomography imaging were collected. Free flap volume was measured by a fellowship-trained neuroradiologist in all cases. Only patients receiving adjuvant radiotherapy with available pre/postradiation imaging were included. Multivariable linear regression modeling for prediction of free flap volume loss was performed with optimization via stepwise elimination. RESULTS: Thirty patients were included for analysis. Mean flap volume loss was 42.7% ± 17.4%. The model predicted flap volume loss in a significant fashion (P = .004, R2 = 0.49) with a mean magnitude of error of 9.8% ± 7.5%. Age (ß = 0.01, P = .003) and RF (ß = -0.01, P = .009) were individual predictors of flap volume loss. CONCLUSIONS: Our model predicts percent free flap volume loss in a significant fashion. Age and RF are individual predictors of free flap volume loss, the latter being a novel finding that is also modifiable through hyperfractionation radiotherapy schedules.

Parotid Warthin's tumor: novel MR imaging score as diagnostic indicator.

OBJECTIVES: Despite known characteristic radiologic and clinical features, differentiation between Warthin's tumor (WT) and other parotid tumors remains challenging. The purpose of this study was to more precisely assess the MR imaging features of WT and to develop a scoring system combining the most specific characteristics. METHODS: A total of 208 patients with parotid gland tumors and presurgical MRI were included. Tumors were divided into 5 histological subtypes, and different MRI features were compared between groups. An MRI scoring test was developed including MR parameters that contributed significantly in distinguishing WT from other tumors. RESULTS: The best MRI features for differentiating between WTs from other tumors included bilaterality (P = 0.002), multifocality (P < 0.001), ADC values <905.1 (P < 0.001), and high signal intensity on T1-W images (P < 0.001). Six or more points on the 14-point scoring MRI scale was associated with an area under the curve of 0.99 (Accuracy of 98%), while a cut-off value of 7 indicated 100% specificity and 100% positive predictive value. CONCLUSIONS: Ill-defined margins, low T1-W signal, and location in the upper 2/3 of the parotid gland excluded WTs in 100% of cases. The proposed scoring method allows WTs to be distinguished from other tumors with high accuracy.