Initial experience of 3 tesla apparent diffusion coefficient values in differentiating benign and malignant thyroid nodules.

PURPOSE: To evaluate the role of diffusion-weighted magnetic resonance imaging (DWMRI) in differentiating benign and malignant thyroid nodules using a 3 Tesla (T) MRI scanner. MATERIALS AND METHODS: Twenty-eight nodules in 25 patients and 14 healthy control cases were included in the study. DWMRI was acquired with 6 b values with a 3T MRI scanner. The apparent diffusion coefficient (ADC) values of the nodules were calculated from reconstructed ADC map images and were compared with the final histopathological diagnoses. RESULTS: The mean ADC value of the benign nodules was 1548 ± 353.4 (×10(-6) mm(2) /s), and the mean ADC of the malignant nodules was 814 ± 177.12 (×10(-6) mm(2) /s). The normal thyroid tissue had a mean ADC value of 1323.43 ± 210.35 × 10(-6) mm(2) /s (958-1689 × 10(-6) mm(2) /s) in the healthy control group. The ADC values were significantly different among the three groups (P = 0.001). An ADC value of 905 × 10(-6) mm(2) /s was determined to be the cutoff value for differentiating benign and malignant nodules, with 90% (55.5-98.3) sensitivity and 100% (81.3-100.0) specificity. CONCLUSION: This study suggests that the ADC values of nodules measured with a 3T MRI scanner could help in differentiating benign thyroid nodules from malignant nodules.

Diffusion tensor imaging in a child with hypertrophic olivary degeneration.

Hypertrophic olivary degeneration (HOD) is caused by disruptive lesions affecting components of the Guillain-Mollaret triangle (GMT). We present conventional magnetic resonance and diffusion tensor imaging (DTI) findings in a 6-year-old girl with HOD after surgery for a midbrain pilocytic astrocytoma. To our knowledge, this is the first dedicated DTI analysis of GMT in a child with HOD in the literature. In our patient, we found higher fractional anisotropy (FA) and axial diffusivity values of the inferior olivary nucleus (ION) and lower FA, but higher radial diffusivity (RD) values of all other GMT components compared to age-matched controls. Increased FA values of the ION may be explained by increased packing of white matter fibers. However, associated hyperintense T2 signal is contradictory and the association between increased FA values and hyperintense T2 signal remains unclear. Low FA and high RD values of the other GMT components likely reflect demyelination with axonal degeneration and correlate well with histopathological findings.

Intracranial Outcomes of De Novo Brain Metastases Treated With Osimertinib Alone in Patients With Newly Diagnosed EGFR-Mutant NSCLC.

Introduction: Patients with EGFR-mutant NSCLC have a high incidence of brain metastases. The EGFR-directed tyrosine kinase inhibitor osimertinib has intracranial activity, making the role of local central nervous system (CNS)-directed therapies, such as radiation and surgery, less clear. Methods: Patients with EGFR-mutant NSCLC and brain metastases who received osimertinib as initial therapy after brain metastasis diagnosis were included. Individual lesion responses were assessed using adapted RANO-BM criteria. CNS progression and local progression of brain metastasis from osimertinib start were analyzed using cumulative incidence treating death as a competing risk. Overall survival was estimated using Kaplan-Meier methodology. Results: There were 36 patients who had a median interval from brain metastasis diagnosis to first-line osimertinib initiation of 25 days. In total, 136 previously untreated brain metastases were tracked from baseline. Overall, 105 lesions (77.2%) had complete response and 31 had partial response reflecting best objective response of 100%. Best response occurred at a median of 96 days (range: 28-1113 d) from baseline magnetic resonance imaging. This reflects a best objective response rate of 100%. Two-year overall survival was 80%. CNS progression rates at 1-, 2-, and 3-years post-osimertinib were 21%, 32%, and 41%, respectively. Lesion-level local failure was estimated to be 0.7% and 4.7% at 1- and 2-years post-osimertinib, respectively. No clinicodemographic factors including brain metastasis number were associated with post-osimertinib progression. Conclusions: Intracranial response to osimertinib is excellent for patients with EGFR-mutant NSCLC with de novo, previously untreated brain metastases. Very low local failure rates support a strategy of upfront osimertinib alone in selected patients.

Cranial intraosseous meningioma: spectrum of neuroimaging findings with respect to histopathological grades in 65 patients.

The aim of this study was to determine various imaging features of intraosseous meningiomas (IOMs) and differentiate low-grade from high-grade tumors. The histopathologic evaluation revealed World Health Organization (WHO) grade I tumor in 56 (86%) patients, grade II in 8 (12%), and grade III in 1 (2%) patient. WHO grade I was considered low grade and II and III were designated as high grade. Hyperostosis was observed most commonly in low-grade IOMs. Mixed hyperostotic/lytic pattern with radial bony spiculations and presence of a scalp mass seem to be more frequently associated with higher-grade IOMs.

The many faces of fungal disease of the paranasal sinuses: CT and MRI findings.

The prevalence of fungal rhinosinusitis has increased worldwide over the last two decades. Fungal rhinosinusitis includes a wide variety of infections, from relatively innocent to rapidly fatal processes. Fungal infection may be one of the most challenging forms of sinonasal pathology to manage, especially the invasive forms, which have high mortality rates. Therefore, it is essential to correctly diagnose and classify fungal disease of paranasal sinuses in order to accurately predict prognosis and implement effective therapy. This essay describes the different manifestations of fungal sinusitis on computed tomography and magnetic resonance imaging to optimize differentiation, and includes correlation with the pathologic classifications.

HASTE diffusion-weighted MRI for the reliable detection of cholesteatoma.

PURPOSE: To assess the detection efficiency of Half-Fourier acquisition single-shot turbo spin-echo (HASTE) diffusion-weighted magnetic resonance imaging (MRI) for cholesteatoma. MATERIALS AND METHODS: A total of 21 patients with suspected primary (n=16) or recurrent cholesteatoma (n=5) underwent MRI in a 1.5 Tesla scanner using an adapted protocol for cholesteatoma detection that included a coronal HASTE diffusion-weighted MRI sequence. The cholesteatoma diagnosis was based on evidence of a hyperintense lesion at b-1000 on diffusion-weighted images. The imaging findings were correlated with findings from surgery or clinical evaluations in all patients. RESULTS: HASTE diffusion-weighted MRI successfully detected 11 primary and 5 recurrent lesions out of 17 cholesteatomas (sensitivity, 94.1%). One primary cholesteatoma with a diameter of 4-5 mm was missed. MRI of patients without cholesteatoma were correctly interpreted as negative for cholesteatoma (specificity, 100%). The positive and negative predictive values for the HASTE diffusion-weighted MRI in detecting cholesteatoma were 100% and 80%, respectively. CONCLUSION: HASTE diffusion-weighted MRI offers great promise for cholesteatoma screening. The addition of this sequence to the posterior fossa MRI protocol may preclude unnecessary cholesteatoma surgery.

Temporomandibular joint herniation into the external ear canal through foramen of Huschke.

Foramen of Huschke, which is also known as the foramen tympanicum, is an anatomical variation of the tympanic portion of the temporal bone. This foramen is located on the anteroinferior aspect of the external auditory canal, posteromedial to the temporomandibular joint. Herein, a rare case of foramen Huschke with a herniation of the soft tissues around the temporomandibular joint that result in severe otalgia and its treatment are presented.

Abscess formation as a complication of a ruptured urachal cyst.

The urachus is a midline tubular structure that extends upward from the dome of the bladder toward the umbilicus. This tubular structure normally involutes before birth, remaining as a fibrous band with no known function. Persistence of all or any portion of the fetal urachus results in several anomalies, the most common of which is the urachal cyst (Yu JS, Kim KW, Lee HJ, Lee YJ, Yoon CS, Kim MJ, Radiographics, 21:451-4611, 2001; Ohgaki M, Higuchi A, Chou H, Takashina K, Kawakami S, Fujita Y, Hagiwara A, Yamagishi H, Surg Today, 33:75-77, 2003). Although most urachal cysts are asymptomatic, there are a few reports about intraperitoneal rupture of infected urachal cysts, all of which caused peritonitis and sepsis (Ohgaki M, Higuchi A, Chou H, Takashina K, Kawakami S, Fujita Y, Hagiwara A, Yamagishi H, Surg Today, 33:75-77, 2003; Kojima Y, Miyake O, Taniwaki H, Morimoto A, Takahashi S, Fujiwara I, Int J Urol, 10:174-176, 2003; Agatstein EH, Stabile BE, Arch Surg, 119:1269-1273, 1984). We report the imaging and operative findings of a patient, presented with a urachal abscess after a spontaneously ruptured urachal cyst.