Malignancy risk of indeterminate lymph node at the central compartment in patients with thyroid cancer and concomitant sonographic thyroiditis.

BACKGROUND: To evaluate the malignancy risk of sonographic (US) indeterminate lymph node (LN)s at the central compartment in thyroid cancer patients with US-thyroiditis (ST). METHODS: Among the central compartments of suspicious, indeterminate, and probably benign LN US categories, the malignancy rates were compared between ST and non-US-thyroiditis (non-ST) groups. Those of indeterminate category were compared with suspicious and probably benign categories. RESULTS: At 531 central compartments from 349 patients, the malignancy rate was lower in ST group (34.4% [44/128]) than non-ST group (43.4% [175/403]), although statistically not significant (p = 0.08). The malignancy rate of indeterminate category in ST group (35.7% [5/14]) was lower than non-ST group (71.9% [23/32]) (p = 0.047). Within ST group, the malignancy rate of indeterminate category (35.7% [5/14]) did not differ from probably benign category (29.1% [30/103]) (p = 0.756), but was lower than suspicious category (81.8% [9/11]) (p = 0.042). CONCLUSIONS: The malignancy risk of US indeterminate LNs at the central compartment in thyroid cancer patients with US thyroiditis was lower than that in patients without US thyroiditis.

A prospective multi-centre study of susceptibility map-weighted MRI for the diagnosis of neurodegenerative parkinsonism.

OBJECTIVES: This study aimed to compare susceptibility map-weighted imaging (SMwI) using various MRI machines (three vendors) with N-3-fluoropropyl-2-ß-carbomethoxy-3-ß-(4-iodophe nyl)nortropane (18F-FP-CIT) PET in the diagnosis of neurodegenerative parkinsonism in a multi-centre setting. METHODS: We prospectively recruited 257 subjects, including 157 patients with neurodegenerative parkinsonism, 54 patients with non-neurodegenerative parkinsonism, and 46 healthy subjects from 10 hospitals between November 2019 and October 2020. All participants underwent both SMwI and 18F-FP-CIT PET. SMwI was interpreted by two independent reviewers for the presence or absence of abnormalities in nigrosome 1, and discrepancies were resolved by consensus. 18F-FP-CIT PET was used as the reference standard. Inter-observer agreement was tested using Cohen's kappa coefficient. McNemar's test was used to test the agreement between the interpretations of SMwI and 18F-FP-CIT PET per participant and substantia nigra (SN). RESULTS: The inter-observer agreement was 0.924 and 0.942 per SN and participant, respectively. The diagnostic sensitivity of SMwI was 97.9% and 99.4% per SN and participant, respectively; its specificity was 95.9% and 95.2%, respectively, and its accuracy was 97.1% and 97.7%, respectively. There was no significant difference between the results of SMwI and 18F-FP-CIT PET (p > 0.05, for both SN and participant). CONCLUSIONS: This study demonstrated that the high diagnostic performance of SMwI was maintained in a multi-centre setting with various MRI scanners, suggesting the generalisability of SMwI for determining nigrostriatal degeneration in patients with parkinsonism. KEY POINTS: • Susceptibility map-weighted imaging helps clinicians to predict nigrostriatal degeneration. • The protocol for susceptibility map-weighted imaging can be standardised across MRI vendors. • Susceptibility map-weighted imaging showed diagnostic performance comparable to that of dopamine transporter PET in a multi-centre setting with various MRI scanners.

Contrast-enhanced Multi-detector CT Examination of Parotid Gland Tumors: Determination of the Most Helpful Scanning Delay for Predicting Histologic Subtypes.

PURPOSE: Although contrast-enhanced CT (computed tomography) is regarded as the preoperative imaging modality of choice for parotid gland tumor, scanning methods are highly variable. We aimed at determining the most helpful scanning delay for predicting histologic subtypes of parotid gland tumors. MATERIAL AND METHODS: Based on the medical record review, we identified 293 patients with 296 parotid gland tumors who underwent uni- or biphasic neck CT examination using a 64-row detector CT with the same acquisition parameters except the scan delays that were: (1) unenhanced, (2) 40 seconds, (3) 50 seconds, and (4) 70 seconds after the beginning of contrast-media injection. Pathologically, the gland tumors (mean size: 26 ± 10.4 mm) consisted of 164 pleomorphic adenomas, 78 Warthin tumors, 23 other benign tumors, and 31 malignant tumors. The mean CT attenuation values (MAV)s from 419 CT images with different scan delays were compared by analysis of variance (ANOVA). RESULTS: On enhanced CT with a 50-second scan delay, Warthin tumors most intensely enhanced and could be distinguished from pleomorphic adenomas and malignant tumors (both p < 0.05). However, with other scan delays, there were no significant differences in MAV between all histologic subtypes of tumors. CONCLUSION: Prediction of histologic subtype, by differentiating Warthin from non-Warthin tumors, was possible only with CT scanning beginning 50 seconds after the start of contrast injection.

Value of CT added to ultrasonography for the diagnosis of lymph node metastasis in patients with thyroid cancer.

BACKGROUND: The benefit of CT for the diagnosis of lymph node metastasis in patients with thyroid cancer is still unclear. METHODS: Three hundred fifty-one patients with thyroid cancers from 7 hospitals were prospectively enrolled in order to compare diagnostic performance between a combination of ultrasound and CT (ultrasound/CT) and ultrasound alone for prediction of lymph node metastasis and to calculate patient-based benefits of CT added to ultrasound. RESULTS: Of 801 pathologically proven neck levels, ultrasound/CT showed higher sensitivities in both central and lateral compartments and improved accuracy in the lateral compartment compared to ultrasound alone. In the retropharyngeal/superior mediastinal compartment, although CT could detect lymph node metastasis an ultrasound could not. Patient-based benefit was demonstrated in 13.1% of patients (46/351), and was higher in patients with cancers >1 cm than cancers ≤1 cm. CONCLUSION: In patients with thyroid cancer, CT improved surgical planning by enhancing the sensitivity for lymph node metastasis and by detecting lymph node metastasis that was overlooked with ultrasound alone.

Temporal bone chondroblastoma: Imaging characteristics with pathologic correlation.

BACKGROUND: Chondroblastoma commonly involves the temporal bone in the craniofacial region, but its imaging features have not been elucidated. This study aimed to describe the imaging features of temporal bone chondroblastoma with their pathologic correlation. METHODS: Radiopathologic correlation was performed in 5 patients with temporal bone chondroblastoma from our database and in 11 patients identified through a PubMed search. RESULTS: The cases of temporal bone chondroblastoma commonly involve the squamous part, temporal and infratemporal fossae, temporomandibular joint, and tympanic cavity, with the following features: high attenuation with calcification; heterogeneity; low signal intensity on T2-weighted imaging with enhancement; a smooth interface to the brain; and strong hypermetabolism on fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT. The heterogeneous low signal intensity on T2-weighted imaging was correlated with various histopathologic components, including calcification and hemosiderin deposition. CONCLUSION: Temporal bone chondroblastoma usually forms as an expansile, heterogeneous, hypermetabolic mass in the middle cranial fossa, frequently with low signal intensity on T2-weighted imaging, reflecting various degrees of calcification and hemosiderin deposition.

Clinical features of recently diagnosed papillary thyroid carcinoma in elderly patients aged 65 and older based on 10 years of sonographic experience at a single institution in Korea.

PURPOSE: The aim of this study was to assess the characteristics of papillary thyroid carcinoma (PTC) in patients aged 65 and older in order to predict postoperative recurrence based on the results of ultrasonographic surveillance. METHODS: Among 1,494 patients (200 male and 1,294 female; mean age, 46.6±11.3 years) who underwent surgery for thyroid cancer at our institution between 2006 and 2015, we retrospectively enrolled 150 PTC patients (29 male and 121 female; mean age, 69.4±4.2 years). To identify the risk factors for recurrence, we analyzed age, gender, multiplicity, size, number, extrathyroidal extension (ETE) of the tumor, lymph node metastasis (LNM), type of surgery, and the dose of radioactive ablation using a Cox regression model to identify hazard ratios (HRs). RESULTS: Among the 115 asymptomatic patients with PTCs detected by screening ultrasonography (n=86), other cross-sectional imaging modalities (computed tomography or positron emission tomography-computed tomography, n=13), or incidentally through a surgical specimen (n=16), 78 patients were confirmed to have papillary thyroid microcarcinomas (PTMCs). The other 35 patients presented with palpable neck masses (n=25), vocal cord palsy (n=9) or blood-tinged sputum (n=1). During the follow-up period (mean, 43.6 months), 17 patients (12.5%) experienced recurrence in the neck. None of the patients died due to PTC-related recurrence or distant metastasis during the follow-up period. Cox regression analysis demonstrated that tumor size (HR, 2.12; P<0.001) and LNM (central LNM: HR, 9.08; P=0.004; lateral LNM: HR, 14.71; P=0.002; both central and lateral LNM: HR, 58.41; P<0.001) significantly increased the recurrence rate. ETE, LNM, and recurrence were significantly less frequent in PTMCs than in non-PTMC (all P<0.001). CONCLUSION: PTCs of small size and absent LNM showed significantly better prognoses in patients 65 years and older.

Assessing the accuracy and reliability of ultrasonographic three-dimensional parathyroid volume measurement in a patient with secondary hyperparathyroidism: a comparison with the two-dimensional conventional method.

PURPOSE: The purpose of this study was to investigate the accuracy and reliability of the semi-automated ultrasonographic volume measurement tool, virtual organ computer-aided analysis (VOCAL), for measuring the volume of parathyroid glands. METHODS: Volume measurements for 40 parathyroid glands were performed in patients with secondary hyperparathyroidism caused by chronic renal failure. The volume of the parathyroid glands was measured twice by experienced radiologists by two-dimensional (2D) and three-dimensional (3D) methods using conventional sonograms and the VOCAL with 30°angle increments before parathyroidectomy. The specimen volume was also measured postoperatively. Intraclass correlation coefficients (ICCs) and the absolute percentage error were used for estimating the reproducibility and accuracy of the two different methods. RESULTS: The ICC value between two measurements of the 2D method and the 3D method was 0.956 and 0.999, respectively. The mean absolute percentage error of the 2D method and the 3D VOCAL technique was 29.56% and 5.78%, respectively. For accuracy and reliability, the plots of the 3D method showed a more compact distribution than those of the 2D method on the Bland-Altman graph. CONCLUSION: The rotational VOCAL method for measuring the parathyroid gland is more accurate and reliable than the conventional 2D measurement. This VOCAL method could be used as a more reliable follow-up imaging modality in a patient with hyperparathyroidism.

The prevalence and features of thyroid pyramidal lobe, accessory thyroid, and ectopic thyroid as assessed by computed tomography: a multicenter study.

BACKGROUND AND PURPOSE: Understanding the computed tomography (CT) characteristics of the pyramidal lobe and other thyroid variations and detecting them accurately using preoperative neck CT will minimize unnecessary remnant thyroid tissue after total thyroidectomy in patients with thyroid cancer. The purpose of the present study was to assess the frequency, location, and size of the pyramidal lobe and other thyroid variations using a large-scaled, multicenter study. METHODS: Neck CT scans for 200 patients were selected from 11 institutions; a total of 2200 patients were included in the study. The patients underwent neck CT for the following reasons: trauma, known thyroid malignancy, cervical lymphadenopathy, palpable neck mass, oropharyngolaryngeal malignancy, vocal cord palsy, postchemotherapy CT follow-up, inflammatory or infectious neck lesion, parathyroid abnormality, and patient request. A single radiologist at each institution retrospectively analyzed 200 neck CT scans. Each radiologist investigated the presence, location, length, volume, and upper end of the pyramidal lobe and its separation or continuity with the main thyroid gland as well as the presence, location, length, and volume of the accessory or ectopic thyroid using a picture archiving and communication system. RESULTS: A pyramidal lobe was present in 44.6% (981/2200) of the patients. The prevalence for the pyramidal lobe at the participating institutions ranged from 28.0% to 55.0% (mean, 44.6%). Pyramidal lobes originating from the left side of the thyroid were most common, and the number of pyramidal lobes showing separation from the main thyroid gland was 90 (9.2%). The mean anteroposterior diameter, transverse diameter, and length of the pyramidal lobe were 2.3, 5.9, and 20.8 mm, respectively. Among both men and women, the most common level of the upper end of the pyramidal lobes was the thyroid cartilage, but there was a significant difference in the frequency of the pyramidal lobe between males and females (p<0.0001). The rate of the pyramidal lobe detection in the 2-mm-slice-thickness group was higher than those in the 2.5- and 3-mm groups (p=0.0003). CONCLUSION: Neck CT is useful for detecting the presence, size, configuration, and location of the pyramidal lobe and other thyroid variations.

Radiofrequency ablation of benign thyroid nodules and recurrent thyroid cancers: consensus statement and recommendations.

Thermal ablation using radiofrequency is a new, minimally invasive modality employed as an alternative to surgery in patients with benign thyroid nodules and recurrent thyroid cancers. The Task Force Committee of the Korean Society of Thyroid Radiology has developed recommendations for the optimal use of radiofrequency ablation for thyroid nodules. These recommendations are based on a comprehensive analysis of the current literature, the results of multicenter studies, and expert consensus.

Anatomical and morphometric study of the bony nasolacrimal canal using computed tomography.

AIMS: To determine the diameters, angles and sectional area of the bony nasolacrimal canal using computed tomography for obtaining detailed anatomical knowledge of the drainage system and utilizing these measurements in planning interventions for nasolacrimal duct obstruction in adults and children. METHODS: Using standard computed tomographic images, we measured the diameters, angles and sectional area of the bony nasolacrimal duct in 228 patients without nasolacrimal duct disease. RESULTS: There was no statistically significant difference in other parameters between males and females. In particular, age had a significant effect on the angle between the bony nasolacrimal canal and the nasal floor in the pediatric patients (<10 years; p = 0.00), and pediatric patients had more acute angles than adult patients (>10 years old). CONCLUSIONS: In nasolacrimal probing of congenital nasolacrimal duct obstruction, the probe should be passed more to the posterior part of the nasal cavity. In other words, the distal part of the probe should form a more obtuse angle with the forehead in pediatric patients than in adults. This study may contribute to the establishment of a detailed anatomical and morphometric baseline of the bony nasolacrimal canal and provide useful information for the planning of interventions for nasolacrimal duct obstruction in adults and children.

Measurement of width and distance of the posterior border of the deep lateral orbital wall using computed tomography.

INTRODUCTION: Techniques of orbital decompression for Graves' ophthalmopathy continue to evolve. Recently the deep lateral orbital wall has been proposed as the most effective and safe site for a decompression procedure associated with the least complications. Anatomic variations with structures like the middle cranial fossa render decompression of the lateral wall more logical. We aimed to understand the anatomic localization and appearance of the lateral orbital wall by measuring the width and distance of the lateral wall on computed tomography (CT). MATERIAL AND METHODS: The medical records of all patients who underwent orbital CT scans for ocular trauma or for confirmation of orbital disease at the Korea University hospital between January 2005 and May 2008 were reviewed retrospectively. All patients had been scanned with the same CT scanner (Philips Brilliance 64 channel CT; Philips Healthcare Systems). Patients who had normal orbits bilaterally were included in this study. The cut in which the lateral rectus muscle was longest and the lateral bony orbit was thickest was selected from the axial and coronal slices. The point where the lateral rectus muscle contacted the the bone was measured on this axial slice. The width of the lateral wall was measured at the level of superior border of the lateral rectus muscle on thickest part of the coronal slice. RESULTS: A total of 334 orbits (167 patients) were included. Patients ranged in age from 7 years to 78 years (median age 41.1 years). The average distance of the lateral wall was 26.0 mm OD and 25.0 mm OS. The average width of the lateral wall was 16.0 mm OD 16.2 mm OS. There was no statistically significant difference between right and left. The patients were divided into 8 age groups by decades. There was no statistically significant difference between the groups in either measurement. CONCLUSION: In this study, we measured the average width and length of the thickest segment of the greater wing of the sphenoid, which can be used as anatomic guidelines during deep lateral orbital decompression surgery, and the basic standard value of the lateral orbital wall.

Isolated petroclival craniopharyngioma with aggressive skull base destruction.

We report a rare case of petroclival craniopharyngioma with no connection to the sellar or suprasellar region. MRI and CT images revealed a homogenously enhancing retroclival solid mass with aggressive skull base destruction, mimicking chordoma or aggressive sarcoma. However, there was no calcification or cystic change found in the mass. Here, we report the clinical features and radiographic investigation of this uncommon craniopharyngioma arising primarily in the petroclival region.

Spontaneous thoracic spinal subdural hematoma associated with fibromuscular dysplasia.

Spontaneous spinal subdural hematoma (SDH) is an uncommon cause of acute spinal cord compression. When it does occur, however, it may have disastrous results and a poor prognosis. The nontraumatic acute spinal SDH usually results from a defect in a hemostatic mechanism (such as coagulopathy or the use of anticoagulant therapy) or from iatrogenic causes (such as spinal puncture). Fibromuscular dysplasia (FMD) is a nonatherosclerotic systemic arteriopathy of unknown cause that typically affects the small and medium arteries in young to middle-aged women. The authors report on their experience with a patient with an acute spontaneous spinal SDH that occurred in conjunction with FMD.

Reversible splenial abnormality in hypoglycemic encephalopathy.

INTRODUCTION: Lesions involving the splenium of the corpus callosum (SCC) have been rarely reported in cases of hypoglycemic brain injury. METHODS: We identified signal abnormalities in the SCC in three adult patients with hypoglycemic encephalopathy by using diffusion-weighted imaging (DWI) on a 1.5-T MR scanner. Repeat DWI was performed in all patients following a marked clinical improvement, and MR angiography and routine MRI were also performed. We examined each patient's detailed medical history and blood laboratory tests in order to exclude other conditions causing similar SCC abnormalities. RESULTS: Initial DWI was performed during which each patient showed altered mental status that was attributed to profound hypoglycemia. We observed an identical pattern of DWI abnormality characterized by high signals in the SCC with apparent diffusion coefficient reductions that were reversed completely within several days following appropriate correction of hypoglycemia. T2-weighted or FLAIR images also showed no residual lesion in the SCC and MR angiography was normal in all patients. CONCLUSION: These case reports suggest that the SCC should be added to the list of selective vulnerability to hypoglycemia and that hypoglycemia, in turn, be included in the differential diagnosis of reversible SCC abnormalities.

Granulocytic sarcoma (chloroma) presenting as a lateral neck mass: initial manifestation of leukemia: a case report.

We present a rare case of granulocytic sarcoma (chloroma) in the lateral neck as an initial manifestation of acute leukemia in a 37-year-old man. The lesion appeared as a solid mass with homogenous contrast enhancement on CT. Recognition of this rare entity is important, because early, aggressive induction chemotherapy can improve prognosis.