Predicting Extrathyroidal Extension in Patients With Papillary Thyroid Microcarcinoma According to a BRAF Mutation

OBJECTIVES: The aim of this study was to evaluate the association between preoperative parameters and extrathyroidal extension (ETE) of papillary thyroid microcarcinoma (PTMC) according to the BRAF mutation and to evaluate the preoperative predictability of ETE. METHODS: We analyzed the medical records of 332 patients with PTMC (140 in the BRAF– group and 192 in the BRAF+ group). The presence of ETE was subjected to a correlation analysis with age, sex, tumor size, clinical nodal status, and ultrasonography (US) findings. Among the US findings, the correlation between tumors and the thyroid capsule was categorized into four groups; US group A, intraparechymal; US group B, tumor abutting the capsule 50% of diameter; and US group D, tumor destroyed the capsule. The predictive value of ETE, including sensitivity, specificity, and positive and negative predictive values were evaluated. RESULTS: Tumor size and US group were significantly correlated with gross ETE in the BRAF– and BRAF+ groups. Tumor size of 0.5 cm and US groups B and C in the BRAF– group were cutoff values for gross ETE, with a negative predictive value of 100%, whereas tumor size of 0.7 cm and US groups A and B in the BRAF+ group had negative predictive values of 92.4% and 100%, respectively. CONCLUSION: Excluding of ETE by US was categorized according to tumor size and US findings. A different categorization to exclude ETE is needed according to the BRAF mutation.

Disconnection of the Rubber Tip of Arrow-Trerotola Percutaneous Thrombolytic Device

A rubber tip disconnection of Arrow-Trerotola percutaneous thrombolytic device (PTD) may occur occasionally. We experienced 5 cases of a rubber tip disconnection among 453 mechanical thrombectomy sessions with the use of PTD. We present a report about these five cases and suggest possible causes for the occurrences.

Serial MR Analysis of Early Permanent and Transient Ischemia in Rats: Diffusion Tensor Imaging and High b Value Diffusion Weighted Imaging

OBJECTIVE: To evaluate the temporal evolution and diagnostic values of the diffusion tensor imaging (DTI) and the high b value diffusion weighted imaging (DWI) in the early permanent and transient cerebral ischemia. MATERIALS AND METHODS: For permanent or 30-minute transient-ischemia induced 30 rats, DTI and DWIs at both high b (b = 3000 s/mm2) and standard b value (b = 1000 s/mm2) were obtained at the following conditions: at 15, 30, 45, 60 minutes after the occlusion of what for hyperacute permanent ischemia; at 1, 3, 5, 7, 9 hours after the occlusion for acute permanent ischemia; and at 15 minutes before reperfusion, 0.5, 2.5, and 24 hours after reperfusion for transient ischemia. The diffusion parameters and their ratios were obtained and compared between different b values, and among different time points and groups, respectively. RESULTS: For both b values, the apparent diffusion coefficient (ADC) ratio decreased for first three hours, and then slightly increased until 9 hours after the occlusion during a gradual continuous increase of DWI signal intensity (SI) ratio, with excellent correlation between ADC ratios and DWI SI ratios. The DWI showed a higher contrast ratio, but the ADC map showed a lower contrast ratio for permanent ischemia at high b value than at standard b value. Fractional anisotropy (FA) increased for 1 hour, then gradually decreased until 9 hours after the occlusion in permanent ischemia and showed transient normalization and secondary decay along with change in ADC in transient ischemia. CONCLUSION: This study presents characteristic initial elevation and secondary decay of FA, higher contrast ratio of DWI, and lower contrast ratio of ADC map at high b value, in addition to the time evolutions of diffusion parameters in early permanent and transient ischemia.

Remote Cerebral and Cerebellar Hemorrhage after Massive Cerebrospinal Fluid Leakage

Dural tears can occur during spinal surgery and may lead to cerebrospinal fluid (CSF) leakage which is rarely involved in remote cerebellar hemorrhage. Only a few of cases of simultaneous cerebral and cerebellar hemorrhage have been reported in the English literature. We experienced a case of multiple remote cerebral and cerebellar hemorrhages in a 63-year-old man who exhibited no significant neurologic deficits after spinal surgery. Magnetic resonance imaging (MRI) performed 4 days after the surgery showed a large amount of CSF leakage in the lumbosacral space. The patient underwent the second surgery for primary repair of the dural defect, but complained of headache after dural repair surgery. Brain MRI taken 6 days after the dural repair surgery revealed multifocal remote intracerebral and cerebellar hemorrhages in the right temporal lobe and both cerebellar hemispheres. We recommend diagnostic imaging to secure early identification and treatment of this complication in order to prevent serious neurologic deficits.

Remote Cerebral and Cerebellar Hemorrhage after Massive Cerebrospinal Fluid Leakage

Dural tears can occur during spinal surgery and may lead to cerebrospinal fluid (CSF) leakage which is rarely involved in remote cerebellar hemorrhage. Only a few of cases of simultaneous cerebral and cerebellar hemorrhage have been reported in the English literature. We experienced a case of multiple remote cerebral and cerebellar hemorrhages in a 63-year-old man who exhibited no significant neurologic deficits after spinal surgery. Magnetic resonance imaging (MRI) performed 4 days after the surgery showed a large amount of CSF leakage in the lumbosacral space. The patient underwent the second surgery for primary repair of the dural defect, but complained of headache after dural repair surgery. Brain MRI taken 6 days after the dural repair surgery revealed multifocal remote intracerebral and cerebellar hemorrhages in the right temporal lobe and both cerebellar hemispheres. We recommend diagnostic imaging to secure early identification and treatment of this complication in order to prevent serious neurologic deficits.

Craniospinal Neurenteric Cysts: Various MR Imaging Features

PURPOSE: Craniospinal neurenteric (NE) cysts are rare developmental non-neoplastic cysts of the central nervous system with diverse MR imaging findings. The purpose of this study was to evaluate various MR imaging findings of intracranial and intraspinal NE cysts. MATERIALS AND METHODS: We retrospectively reviewed the MR imaging findings of six NE cysts that were confirmed by pathology. We evaluated anatomic location, signal intensity, size and enhancement pattern of NE cysts. RESULTS: Two intracranial lesions were located extra-axially in the cerebellopontine angle and quadrigeminal cisterns. Three spinal lesions were intraduralextramedullary cysts, located ventral to the spinal cord, but one thoracic lesion was an intramedullary cyst. The signal intensity of the cysts was hyperintense on T1-weighted images as compared with the cerebrospinal fluid (CSF) for two intracranial lesions and one cervical lesion. In addition, all intracranial lesions showed diffusion restriction. For the remaining three spinal lesions, the signal intensity was nearly the same as the signal intensity of the CSF as seen on both T1- and T2-weighted images. On contrast-enhanced studies, two intracranial cysts showed a small nodular enhancement and one thoracic spinal lesion showed rim enhancement. CONCLUSION: NE cysts have various locations, signal intensities, and possible focal nodular or rim enhancement. Therefore, NE cysts can be included in the differential diagnosis of various craniospinal cystic or tumorous cystic lesions.

Diagnostic Benefit of Thyroglobulin Measurement in Fine-Needle Aspiration for Diagnosing Metastatic Cervical Lymph Nodes from Papillary Thyroid Cancer: Correlations with US Features

OBJECTIVE: Our goals were to determine the added value of fine-needle aspiration biopsy (FNAB)-thyroglobulin (Tg) measurements over FNAB-cytology alone for diagnosing metastatic nodes, and to determine whether the ultrasound features of lymph nodes can be used to identify lymph nodes that may benefit from FNAB-Tg measurement in patients with papillary thyroid cancer. MATERIALS AND METHODS: We retrospectively evaluated 76 surgically proven cervical lymph nodes. Twenty-nine patients were awaiting surgery and 18 patients had undergone thyroid surgery for papillary thyroid cancer. Ultrasound-guided FNAB and Tg measurements were performed and the ultrasound features were evaluated. RESULTS: The accuracies, sensitivities, and specificities of FNAB-cytology, FNAB-Tg, and combined FNAB-Tg/cytology were 90%, 80%, and 100%; 92%, 95%, and 90%; and 93%, 96%, and 90%, respectively. The diagnostic sensitivity of FNAB-Tg for metastatic nodes was significantly higher than that of FNAB-cytology (p = 0.011). Furthermore, combined FNAB-Tg/cytology significantly increased sensitivity (p = 0.002) and accuracy (p = 0.03) as compared with FNAB-cytology. CONCLUSION: Combined FNAB-Tg/cytology is significantly more sensitive and accurate at detecting metastatic nodes than FNAB-cytology alone. FNAB-Tg was better at diagnosing metastases in small lymph nodes.

In Vivo MR Imaging of Magnetically Labeled Mesenchymal Stem Cells in a Rat Model of Renal Ischemia

OBJECTIVE: This study was designed to evaluate in vivo MR imaging for the depiction of intraarterially injected superparamagnetic iron oxide (SPIO)-labeled mesenchymal stem cells (MSCs) in an experimental rat model of renal ischemia. MATERIALS AND METHODS: Left renal ischemia was induced in 12 male Sprague-Dawley rats by use of the catheter lodging method. In vivo MR signal intensity variations depicted on T2*-weighted sequences were evaluated in both the left and right kidneys prior to injection (n = 2), two hours (n = 4), 15 hours (n = 2), 30 hours (n = 2) and 72 hours (n = 2) after injection of SPIO-labeled MSCs in both kidneys. Signal intensity variations were correlated with the number of Prussian blue stain-positive cells as visualized in histological specimens. RESULTS: In an in vivo study, it was determined that there was a significant difference in signal intensity variation for both the left and right cortex (40.8 +/- 4.12 and 26.4 +/- 7.92, respectively) and for both the left and right medulla (23.2 +/- 3.32 and 15.2 +/- 3.31, respectively) until two hours after injection (p < 0.05). In addition, signal intensity variation in the left renal cortex was well correlated with the number of Prussian blue stain-positive cells per high power field (r = 0.98, p < 0.05). CONCLUSION: Intraarterial injected SPIO-labeled MSCs in an experimental rat model of renal ischemia can be detected with the use of in vivo MR imaging immediately after injection.

Interventional Management after Gastrectomy: The Spectrum of Imaging Findings and Procedures

Gastric cancer is the most common cancer in Korea, and is often treated by surgical resection. Many postoperative complications or tumor recurrence, however, are managed by the use of imaging-guided interventions. This review describes the spectrum of postoperative complications that occur following gastrectomy, with an emphasis on the interventional procedures used to manage postoperative complications and tumor recurrence.

A New Ultrasound-Guided Puncture Device with Augmented Degrees of Performance Freedom and Ability to Attach to Most Convex Probes

PURPOSE: To evaluate the performance of a newly-designed ultrasound (US)-guided puncture device. MATERIALS AND METHODS: A newly-designed US-guided puncture device was composed of a guide segment and an attachable segment. The guide segment allowed the needle to be placed in the plane of US view with a maximal degree of freedom, and the attachable segment was designed to attach to most convex US probes. Six operators punctured 144 targets in phantoms using either the new device (n = 72) or free-hand technique (n = 72). The number of required needle passages and the necessary procedure times were compared between the two groups. RESULTS: The number of required needle passages and the necessary procedure time were significantly reduced in five operators when the newly-designed US-guided puncture device was used (p < 0.05). CONCLUSION: A newly-designed US-guided puncture device, which allows for a maximal degree of freedom in needle placement and can attach to most convex US probes, showed good performance in our study.

Serial CT Findings of Paragonimus Infested Dogs and the Micro-CT Findings of the Worm Cysts

OBJECTIVE: To investigate the serial CT findings of Paragonimus westermani infected dogs and the microscopic structures of the worm cysts using Micro-CT. MATERIALS AND METHODS: This study was approved by the committee on animal research at our institution. Fifteen dogs infected with P. westermani underwent serial contrast-enhanced CT scans at pre-infection, after 10 days of infection, and monthly thereafter until six months for determining the radiologic-pathologic correlation. Three dogs (one dog each time) were sacrificed at 1, 3 and 6 months, respectively. After fixation of the lungs, both multi-detector CT and Micro-CT were performed for examining the worm cysts. RESULTS: The initial findings were pleural effusion and/or subpleural ground-glass opacities or linear opacities at day 10. At day 30, subpleural and peribronchial nodules appeared with hydropneumothorax and abdominal or chest wall air bubbles. Cavitary change and bronchial dilatation began to be seen on CT scan at day 30 and this was mostly seen together with mediastinal lymphadenopathy at day 60. Thereafter, subpleural ground-glass opacities and nodules with or without cavitary changes were persistently observed until day 180. After cavitary change of the nodules, the migratory features of the subpleural or peribronchial nodules were seen on all the serial CT scans. Micro-CT showed that the cyst wall contained dilated interconnected tubular structures, which had communications with the cavity and the adjacent distal bronchus. CONCLUSION: The CT findings of paragonimiasis depend on the migratory stage of the worms. The worm cyst can have numerous interconnected tubular channels within its own wall and these channels have connections with the cavity and the adjacent distal bronchus.

FDG-PET for Evaluating the Antitumor Effect of Intraarterial 3-Bromopyruvate Administration in a Rabbit VX2 Liver Tumor Model

OBJECTIVE: We wanted to investigate the feasibility of using FDG-PET for evaluating the antitumor effect of intraarterial administration of a hexokinase II inhibitor, 3-bromopyruvate (3-BrPA), in a rabbit VX2 liver tumor model. MATERIALS AND METHODS: VX2 carcinoma was grown in the livers of ten rabbits. Two weeks later, liver CT was performed to confirm appropriate tumor growth for the experiment. After tumor volume-matched grouping of the rabbits, transcatheter intraarterial administration of 3-BrPA was performed (1 mM and 5 mM in five animals each, respectively). FDG-PET scan was performed the day before, immediately after and a week after 3-BrPA administration. FDG uptake was semiquantified by measuring the standardized uptake value (SUV). A week after treatment, the experimental animals were sacrificed and the necrosis rates of the tumors were calculated based on the histopathology. RESULTS: The SUV of the VX2 tumors before treatment (3.87+/-1.51[mean+/-SD]) was significantly higher than that of nontumorous liver parenchyma (1.72+/-0.34) (p < 0.0001, Mann-Whitney U test). The SUV was significantly decreased immediately after 3-BrPA administration (2.05+/-1.21) (p = 0.002, Wilcoxon signed rank test). On the one-week follow up PET scan, the FDG uptake remained significantly lower (SUV 1.41+/-0.73) than that before treatment (p = 0.002), although three out of ten animals showed a slightly increasing tendency for the FDG uptake. The tumor necrosis rate ranged from 50.00% to 99.90% (85.48%+/-15.87). There was no significant correlation between the SUV or the SUV decrease rate and the tumor necrosis rate in that range. CONCLUSION: Even though FDG-PET cannot exactly reflect the tumor necrosis rate, FDG-PET is a useful modality for the early assessment of the antitumor effect of intraarterial administration of 3-BrPA in VX2 liver tumor.

Multiple Linear Analysis for Generating Parametric Images of Irreversible Radiotracer / 핵의학분자영상

PURPOSE: Biological parameters can be quantified using dynamic PET data with compartment modeling and Nonlinear Least Square (NLS) estimation. However, the generation of parametric images using the NLS is not appropriate because of the initial value problem and excessive computation time. In irreversible model, Patlak graphical analysis (PGA) has been commonly used as an alternative to the NLS method. In PGA, however, the start time (t*, time where linear phase starts) has to be determined. In this study, we suggest a new Multiple Linear Analysis for irreversible radiotracer (MLAIR) to estimate fluoride bone influx rate (Ki). METHODS: [18F]Fluoride dynamic PET scans was acquired for 60 min in three normal mini-pigs. The plasma input curve was derived using blood sampling from the femoral artery. Tissue time-activity curves were measured by drawing region of interests (ROIs) on the femur head, vertebra, and muscle. Parametric images of Ki were generated using MLAIR and PGA methods. RESULT: In ROI analysis, estimated Ki values using MLAIR and PGA method was slightly higher than those of NLS, but the results of MLAIR and PGA were equivalent. Patlak slopes (Ki) were changed with different t* in low uptake region. Compared with PGA, the quality of parametric image was considerably improved using new method. CONCLUSION: The results showed that the MLAIR was efficient and robust method for the generation of Ki parametric image from [18F]Fluoride PET. It will be also a good alternative to PGA for the radiotracers with irreversible three compartment model.

Differentiation of Hyperplastic from Metastatic Lymph Nodes Using a Lymph Node Specific MR Contrast Agent Gadofluorine M

PURPOSE: We wanted to evaluate the value of a lymph node specific MR contrast agent, Gadofluorine M, for the differentiation of hyperplastic and metastatic lymph nodes. MATERIALS AND METHODS: This study included thirty-one rabbits. In ten rabbits, an injection of egg yolk or feces of rat into the calf muscles induced hyperplasia of the lymph node. In sixteen rabbits, metastasis of the lymph node was induced by implantation of VX2 tumor. Five rabbits were normal control models. We acquired the T1-, T2-weighted and SPGR coronal imaging before enhancement with 1.5 T MR. After injection of Gadofluorine M (5 micromol/mL, total amount: 4 mL) interstitially into the interdigital skin fold of the hind limb, we acquired the SPGR coronal imaging at 15, 30, 60 and 90 minutes. We calculated the signal-to-noise ratios on the sequential images, and we recorded the number, size and location of the popliteal and iliac lymph nodes. Three readers assessed the state of the lymph nodes according to the pattern of enhancement: they were deemed hyperplastic nodes when totally enhanced and as metastatic nodes when there was no or partial enhancement. We also compared the imaging patterns with the histopathological results. RESULTS: Among the 26 hyperplasia- or metastasis-induced rabbits, two rabbits were excluded because of failure to be enhanced. Histopathologic evaluation of the 24 rabbits detected one hundred seventeen lymph nodes: forty-six lymph nodes in nine hyperplasia-induced rabbits and seventy-one (metastasis in twenty-eight) lymph nodes in fifteen metastasis-induced rabbits. Out of one hundred two lymph nodes that were larger than 5 mm in size, MR enabled us to detect one hundred one lymph nodes (99.1%). The means of sensitivity, specificity, and the positive and negative predictive values for the diagnosis of lymph node metastasis by three readers were 97.6% (82/84), 98.2% (215/219), 95.3% (82/86), and 99.1% (215/217), respectively (p < 0.05). CONCLUSION: Interstitial MR lymphography using Gadofluorine M showed excellent results in differentiating hyperplastic from metastatic lymph nodes.

Detection of the Anatomic Structure and Pathology in Animal Lung Specimens: Comparison of Micro CT and Multi-Detector Row CT

PURPOSE: We wanted to compare the capability of micro CT and the clinically available thin-slice multi-detector row CT (MDCT) for demonstrating fine anatomic structures and pathological lesions in formalin-fixed lung specimens. MATERIALS AND METHODS: The porcine lung with shark liver oil-induced lipoid pneumonia and the canine lung with pulmonary paragonimiasis were fixed by ventilating them with formalin vapor, and they were then sliced into one-centimeter thick sections. Micro CT (section thickness, 18 micrometer) and MDCT (section thickness, 0.75 mm) images were acquired in four of the lung slices of the lipoid pneumonia specimen and in five of the lung slices of the paragonimiasis specimen. On 62 pairs of micro CT and MDCT images, 169 pairs of rectangular ROIs were manually drawn in the corresponding locations. Two chest radiologists recorded the detectability of three kinds of anatomic structures (lobular core structure, interlobular septum and small bronchiolar lumen) and two kinds of pathological lesions (ground-glass opacity and consolidation) with using a five-point scale. The statistical comparison was performed by using the Wilcoxon signed rank test. Interobserver agreement was evaluated with kappa statistics. RESULTS: For all observers, all the kinds of anatomic structures and pathological lesions were detected better on the micro CT images than on the MDCT images (p<0.01). Agreement was fair between two observers (kappa = 0.38, p<0.001). CONCLUSION: The fine anatomic structures and pathological lesions of the lung were more accurately demonstrated on micro CT than on thin-slice MDCT in the inflated and fixed lung specimens.

CT Analysis of the Anterior Mediastinum in Idiopathic Pulmonary Fibrosis and Nonspecific Interstitial Pneumonia

OBJECTIVE: We wanted to determine whether the amount and shape of the anterior mediastinal fat in the patients suffering with usual interstitial pneumonia (UIP) or nonspecific interstitial pneumonia (NSIP) was different from those of the normal control group. MATERIALS AND METHODS: We selected patients who suffered with UIP (n = 26) and NSIP (n = 26) who had undergone CT scans. Twenty-six controls were selected from individuals with normal CT findings and normal pulmonary function tests. All three groups (n = 78) were individually matched for age and gender. The amounts of anterior mediastinal fat, and the retrosternal anteroposterior (AP) and transverse dimensions of the anterior mediastinal fat were compared by one-way analysis of variance and Bonferroni's test. The shapes of the anterior mediastinum were compared using the Chi-square test. Exact logistic regression analysis and polychotomous logistic regression analysis were employed to assess whether the patients with NSIP or UIP had a tendency to show a convex shape of their anterior mediastinal fat. RESULTS: The amount of anterior mediastinal fat was not different among the three groups (p = 0.175). For the UIP patients, the retrosternal AP dimension of the anterior mediastinal fat was shorter (p = 0.037) and the transverse dimension of the anterior mediastinal fat was longer (p = 0.001) than those of the normal control group. For the NSIP patients, only the transverse dimension was significantly longer than those of the normal control group (p < 0.001). The convex shape of the anterior mediastinum was predictive of NSIP (OR = 19.7, CI 3.32-infinity, p < 0.001) and UIP (OR = 24.42, CI 4.06-infinity, p < 0.001). CONCLUSION: For UIP patients, the retrosternal AP and transverse dimensions are different from those of normal individuals, whereas the amounts of anterior mediastinal fat are similar. UIP and NSIP patients have a tendency to have a convex shape of their anterior mediastinal fat.

Mediastinal and Extrapleural Fat Hypertrophy in Idiopathic Pulmonary Fibrosis on High-resolution CT: Comparison with Normal Individuals

PURPOSE: We wished to compare the amount of mediastinal and extrapleural fat on high resolution CT for patients with idiopathic pulmonary fibrosis (IPF) with that of normal individuals, and we wished to evaluate the correlation between the amount of fat and the degree of pulmonary fibrosis. MATERIALS AND METHODS: We selected a group of 25 patients with radiologically and clinically diagnosed IPF and we also selected another group of 25 age and gender-matched patients having no abnormalities on pulmonary function testing as well as HRCT as controls from our radiologic database search (mean age: 59 years, M:F=11:14). We measured the area of mediastinal and extrapleural fat at the levels of the aortic arch and at the origin of the right pulmonary artery and right inferior pulmonary vein on three sections of HRCT by using software (Rapidia; 3DMED, Seoul, Korea). The total amount of fat was calculated by summing up the areas of the mediastinal and extrapleural fat, which is corrected by the body mass index; we also evaluated statistical differences between the two groups. At same sections of CT, the ratio (%) of the honeycombing area to the total areas of the lung was calculated. We evaluated the relationship between the amount of extrapleural or mediastinal fat with the ratio (%) of the honeycombing area. RESULTS: The total amount of fat in patients with IPF and normal individuals were 67.24+/-19.03 cm2 and 32.55+/-11.91 cm2, respectively. The fat amount corrected by body mass index was 280.48+/-74.43 mm2/kg/m2 in the IPF patients and 137.06+/-41.76 mm2/kg/m2 in normal individuals. The differences between two groups for the total amount of fat and fat amount, as corrected for by the body mass index, were statistically significant (p<0.0001). The ratio (%) of the honeycombing area and the total amount of fat showed a moderate correlation (rho= 0.43, p= 0.032). CONCLUSION:Patients with IPF have a larger amount of mediastinal and extrapleural fat than normal individuals. The hypertrophy of mediastinal and extrapleural fat in IPF may be affected by the severity of the interstitial fibrosis of the lung.