Feasibility of Single-Shot Whole Thoracic Time-Resolved MR Angiography to Evaluate Patients with Multiple Pulmonary Arteriovenous Malformations

Objective@#To evaluate the feasibility of single-shot whole thoracic time-resolved MR angiography (TR-MRA) to identify the feeding arteries of pulmonary arteriovenous malformations (PAVMs) and reperfusion of the lesion after embolization in patients with multiple PAVMs. @*Materials and Methods@#Nine patients (8 females and 1 male; age range, 23–65 years) with a total of 62 PAVMs who underwent percutaneous embolization for multiple PAVMs and were subsequently followed up using TR-MRA and CT obtained within 6 months from each other were retrospectively reviewed. All imaging analyses were performed by two independent readers blinded to clinical information. The visibility of the feeding arteries on maximum intensity projection (MIP) reconstruction and multiplanar reconstruction (MPR) TR-MRA images was evaluated by comparing them to CT as a reference. The accuracy of TR-MRA for diagnosing reperfusion of the PAVM after embolization was assessed in a subgroup with angiographic confirmation. The reliability between the readers in interpreting the TR-MRA results was analyzed using kappa (κ) statistics. @*Results@#Feeding arteries were visible on the original MIP images of TR-MRA in 82.3% (51/62) and 85.5% (53/62) of readers 1 and 2, respectively. Using the MPR, the rates increased to 93.5% (58/62) and 95.2% (59/62), respectively (κ = 0.760 and 0.792, respectively). Factors for invisibility were the course of feeding arteries in the anteroposterior plane, proximity to large enhancing vessels, adjacency to the chest wall, pulsation of the heart, and small feeding arteries. Thirty-seven PAVMs in five patients had angiographic confirmation of reperfusion status after embolization (32 occlusions and 5 reperfusions).TR-MRA showed 100% (5/5) sensitivity and 100% (32/32, including three cases in which the feeding arteries were not visible on TR-MRA) specificity for both readers. @*Conclusion@#Single-shot whole thoracic TR-MRA with MPR showed good visibility of the feeding arteries of PAVMs and high accuracy in diagnosing reperfusion after embolization. Single-shot whole thoracic TR-MRA may be a feasible method for the follow-up of patients with multiple PAVMs.

Magnetization Transfer Contrast Angiography for Organized Thrombosed Intracranial Aneurysm in TOF MR Angiography: a Case Report

A 66-year-old woman was referred for treatment of incidental detection of two intracranial aneurysms. Time-of-flight MR angiography (TOF MRA) revealed two aneurysms at the M1 segment of the right middle cerebral artery, and clinoid segment of left internal carotid artery, respectively. On digital subtraction angiography, there was a saccular aneurysm on the left internal carotid artery, but the other aneurysm was not detected on the right middle cerebral artery. Based on comprehensive review of imaging findings, organized thrombosed aneurysm was judged as the most likely diagnosis. In the presented report, magnetization transfer (MT) pulse to TOF MRA was used, to differentiate aneurysm-mimicking lesion on TOF MRA. We report that MT technique could be effective in differentiating true aneurysm, from possible T1 high signal artifact on TOF MRA.

Hemorrhagic Rupture of Arachnoid Cyst into the Intradural Space

A 7-year-old boy, diagnosed with an arachnoid cyst and subdural effusion on initial MRI, was admitted with left limb weakness and no history of head trauma. A subsequent follow-up MRI showed different stages of hematoma within multilayered enhancing membranes and in the arachnoid cyst, which was separated by the cerebrospinal fluid cleft. Craniotomy and fenestration of the cyst wall and hematoma removal were performed. The patient was diagnosed as a having a hemorrhagic rupture of an arachnoid cyst into the intradural space, probably via some one-way valve-like defect, based on the MRI and surgical findings. The MRI features and possible mechanism of this rare disease are discussed within the literature review.

The Pallidal Index in Patients with Acute-on-Chronic Liver Disease: Is It a Predictor of Severe Hepatic Encephalopathy?

PURPOSE: To evaluate the clinical significance of T1 high signal intensity on the globus pallidus as a predictor of severe hepatic encephalopathy in patients with acute-on-chronic liver failure (ACLF), which is a distinct syndrome characterized by multi-organ dysfunction including cerebral failure. MATERIALS AND METHODS: From January 2002 to April 2014, we retrospectively reviewed the magnetic resonance imaging (MRI) findings and clinical and magnetic resonance (MR) features of 74 consecutive patients (44 men and 30 women; mean age, 59.5 years) with liver cirrhosis. The chronic liver failure-sequential organ failure assessment score was used to diagnose ACLF. The pallidal index (PI), calculated by dividing the mean signal intensity of the globus pallidus by that of the subcortical frontal white matter were compared according to ACLF. The PI was compared with the Model for End-Stage Liver Disease (MELD) score in predicting the development of ACLF. RESULTS: Fifteen patients who were diagnosed with ACLF had higher hepatic encephalopathy grades (initial, P = 0.024; follow-up, P = 0.002), MELD scores (P < 0.001), and PI (P = 0.048). In the ACLF group, the mean PI in patients with cerebral failure was significantly higher than that in the patients without cerebral failure (1.33 vs. 1.20, P = 0.039). In patients with ACLF, the area under the curve (AUC) for PI was 0.680 (95% confidence intervals [CI], 0.52–0.85), which was significantly lower than that for the MELD score (AUC, 0.88; 95% CI, 0.77–0.99) (P = 0.04). CONCLUSION: The PI can be an ancillary biomarker for predicting the development of ACLF and severe hepatic encephalopathy.

The Pallidal Index in Patients with Acute-on-Chronic Liver Disease: Is It a Predictor of Severe Hepatic Encephalopathy?

PURPOSE: To evaluate the clinical significance of T1 high signal intensity on the globus pallidus as a predictor of severe hepatic encephalopathy in patients with acute-on-chronic liver failure (ACLF), which is a distinct syndrome characterized by multi-organ dysfunction including cerebral failure. MATERIALS AND METHODS: From January 2002 to April 2014, we retrospectively reviewed the magnetic resonance imaging (MRI) findings and clinical and magnetic resonance (MR) features of 74 consecutive patients (44 men and 30 women; mean age, 59.5 years) with liver cirrhosis. The chronic liver failure-sequential organ failure assessment score was used to diagnose ACLF. The pallidal index (PI), calculated by dividing the mean signal intensity of the globus pallidus by that of the subcortical frontal white matter were compared according to ACLF. The PI was compared with the Model for End-Stage Liver Disease (MELD) score in predicting the development of ACLF. RESULTS: Fifteen patients who were diagnosed with ACLF had higher hepatic encephalopathy grades (initial, P = 0.024; follow-up, P = 0.002), MELD scores (P < 0.001), and PI (P = 0.048). In the ACLF group, the mean PI in patients with cerebral failure was significantly higher than that in the patients without cerebral failure (1.33 vs. 1.20, P = 0.039). In patients with ACLF, the area under the curve (AUC) for PI was 0.680 (95% confidence intervals [CI], 0.52–0.85), which was significantly lower than that for the MELD score (AUC, 0.88; 95% CI, 0.77–0.99) (P = 0.04). CONCLUSION: The PI can be an ancillary biomarker for predicting the development of ACLF and severe hepatic encephalopathy.

Ultrasonography Diagnosis and Imaging-Based Management of Thyroid Nodules: Revised Korean Society of Thyroid Radiology Consensus Statement and Recommendations

The rate of detection of thyroid nodules and carcinomas has increased with the widespread use of ultrasonography (US), which is the mainstay for the detection and risk stratification of thyroid nodules as well as for providing guidance for their biopsy and nonsurgical treatment. The Korean Society of Thyroid Radiology (KSThR) published their first recommendations for the US-based diagnosis and management of thyroid nodules in 2011. These recommendations have been used as the standard guidelines for the past several years in Korea. Lately, the application of US has been further emphasized for the personalized management of patients with thyroid nodules. The Task Force on Thyroid Nodules of the KSThR has revised the recommendations for the ultrasound diagnosis and imaging-based management of thyroid nodules. The review and recommendations in this report have been based on a comprehensive analysis of the current literature and the consensus of experts.

A Case Report of the Angiosarcoma Involving Epicranial Muscle and Fascia : Is the Occipitofrontalis Muscle Composed of Two Different Muscles?

The occipitofrontalis muscle is generally regarded as one muscle composed of two muscle bellies joined through the galea aponeurotica. However, two muscle bellies have different embryological origin, anatomical function and innervations. We report a case of angiosarcoma of the scalp in a 63-year-old man whose MR showed that the superficial fascia overlying the occipital belly becomes the temporoparietal fascia and ends at the superior end of the frontal belly. Beneath the superficial fascia, the occipital belly of the occipitofrontalis muscle becomes the galea aponeurotica and inserts into the underside of the frontal belly. The presented case report supported the concept of which the occipitofrontalis muscle appears to be composed of two anatomically different muscles.

Incidental Breast Lesions Identified by 18F-FDG PET/CT: Which Clinical Variables Differentiate between Benign and Malignant Breast Lesions? / 한국유방암학회지

PURPOSE: The aim of our study was to evaluate the risk of malignancy and to determine which clinical variables differentiate between benign and malignant focal breast lesions found incidentally on 18F-flourodeoxyglucose positron emission tomography and computed tomography (FDG PET/CT). METHODS: From March 2005 to October 2011, 21,224 women with no history of breast cancer underwent FDG PET/CT at three university-affiliated hospitals. We retrospectively identified 214 patients with incidental focal hypermetabolic breast lesions and grouped them into benign and malignant lesion groups. Of the 214 patients, 82 patients with 91 lesions were included in this study. All lesions were confirmed histologically or were assessed by follow-up imaging for greater than 2 years. The patient age, maximum standardized uptake value (SUVmax), lesion size on ultrasonography (US), and Breast Imaging-Reporting and Data System (BI-RADS) category on US in conjunction with mammography were compared between the groups. Multivariate logistic regression analysis was used to identify independent factors associated with malignancy. RESULTS: The risk of malignancy was 29.7% (27/91) in breast incidentalomas detected by FDG PET/CT. The univariate analysis showed that the patient age, SUVmax, tumor size, and BI-RADS category differed significantly between the malignant and benign groups. The multivariate analysis showed that the BI-RADS category was the only significant factor differentiating benign from malignant lesions (p=0.002). CONCLUSION: BIRADS category based on US in conjunction with mammography was the only useful tool to differentiate between malignant and benign lesions in breast incidentalomas on FDG PET/CT.

A Case of Anterograde Amnesia with Bilateral Hippocampus Involvement After Acute Glufosinate Ammonium Intoxication

A 51-year-old man developed anterograde amnesia following the ingestion of glufosinate ammonium. Brain MRI revealed hyperintense lesions involving the bilateral hippocampus and parahippocampal gyrus, and the right occipital lobe. The mechanism underlying acute glufosinate ammonium intoxication and the differential diagnosis of hippocampal lesions are discussed.

Medial Longitudinal Fasciculus on MRI in a Patient with Internuclear Ophthalmoparesis: A Case Report

The medial longitudinal fasciculus (MLF) is myelinated composite tract, lying near the midline, ventral to periaqueductal grey matter that plays a key role in coordinating eye movements. A lesion of the MLF results in an ipsilateral adduction deficit and a contralateral abducting nystagmus, referred to as an internuclear ophthalmoparesis. The blended tract with adjacent white matter in pons and midbrain is indistinguishable on brain imaging such as CT and MRI. Until now, to the best of our knowledge, MLF is not delineated on in vivo MRI. We present a case showing the whole connecting courses of MLF lesion on MRI in a patient with inflammatory demyelinating disorder.

Irreversible Hemorrhagic Complication of Recurrent Posterior Reversible Encephalopathy Syndrome in a Patient with Systemic Lupus Erythematosus

Although most cases of posterior reversible encephalopathy syndrome (PRES) are reversible, irreversible lesions as a form of hemorrhage or infarction have been described. PRES as a complication of systemic lupus erythematosus (PRES-SLE) is associated with hypertension or use of immunosuppressive agents. We present a case of recurrent atypical PRES-SLE, which showed restricted diffusion in the first manifestation of SLE, resulted in parenchymal hemorrhagic transformations in the recurrent episode.

Imaging Finding of Malignant Melanoma of Eustachian Tube with Extension to Middle Ear Cavity: Case Report

We report a case of malignant melanoma of Eustachian tube with extension to the middle ear cavity and nasopharynx in a 51-year-old woman who presented with right ear fullness. Computed tomography showed a soft tissue mass in the middle ear cavity and causedthe widening and eroding of the bony eustachian tube. Magnetic resonance imaging showed well enhancing mass in eustachian tube extending nasopharynx to middle ear cavity. A biopsy of the middle ear cavity mass revealed a malignant amelanotic melanoma.

Role of MRI in Diagnostic Evaluation of Papillary Lesions of the Breast

PURPOSE: To evaluate the role of magnetic resonance imaging (MRI) in the diagnosis of papillary lesions of the breast. MATERIALS AND METHODS: Among 45 papillary lesions diagnosed at ultrasonography-guided core biopsy (USCB), 27 benign papillary lesions in 22 patients who underwent breast MRI were reviewed. The excsional biopsy was performed in 1-10 days after MRI was done. In MRI findings, lesions were considered suspicious if they show irregular, rim enhancement, or linear enhancement in morphologic evaluation, or washout enhancement pattern of delayed phase in dynamic enhancement characteristics. Diffusion-weighted images were analyzed according to visibility of lesions. MRI findings were correlated with pathologic results at excisional biopsy. RESULTS: At excisional biopsy, two lesions (9%) were diagnosed malignant in 22 benign papillary lesions without atypia by USCB and 4 (80%) were malignant in 5 benign papillary lesions with atypia by USCB. Among 18 lesions detected on MRI, 16 lesions showed suspicious findings on MRI, 11 lesions (69%) were diagnosed as benign and 5 (31%) were malignant. Among 12 lesions detected on diffusion weighted imaging, 10 lesions were diagnosed as benign and 2 were malignant. MRI findings were not significantly correlated with pathologic results at excisional biopsy. CONCLUSION: MRI findings were not useful to predict malignancy in benign papillary lesions diagnosed at USCB, because MRI findings of these were mostly suspicious (88.9%, 16/18). The benign papillary lesion should be included in the false positive lesion on breast MRI.

Role of MRI in Diagnostic Evaluation of Papillary Lesions of the Breast

PURPOSE: To evaluate the role of magnetic resonance imaging (MRI) in the diagnosis of papillary lesions of the breast. MATERIALS AND METHODS: Among 45 papillary lesions diagnosed at ultrasonography-guided core biopsy (USCB), 27 benign papillary lesions in 22 patients who underwent breast MRI were reviewed. The excsional biopsy was performed in 1-10 days after MRI was done. In MRI findings, lesions were considered suspicious if they show irregular, rim enhancement, or linear enhancement in morphologic evaluation, or washout enhancement pattern of delayed phase in dynamic enhancement characteristics. Diffusion-weighted images were analyzed according to visibility of lesions. MRI findings were correlated with pathologic results at excisional biopsy. RESULTS: At excisional biopsy, two lesions (9%) were diagnosed malignant in 22 benign papillary lesions without atypia by USCB and 4 (80%) were malignant in 5 benign papillary lesions with atypia by USCB. Among 18 lesions detected on MRI, 16 lesions showed suspicious findings on MRI, 11 lesions (69%) were diagnosed as benign and 5 (31%) were malignant. Among 12 lesions detected on diffusion weighted imaging, 10 lesions were diagnosed as benign and 2 were malignant. MRI findings were not significantly correlated with pathologic results at excisional biopsy. CONCLUSION: MRI findings were not useful to predict malignancy in benign papillary lesions diagnosed at USCB, because MRI findings of these were mostly suspicious (88.9%, 16/18). The benign papillary lesion should be included in the false positive lesion on breast MRI.

Detection of the Transition Zone and Adhesions in the Diagnosis of Adhesive Small-bowel Obstruction: the Added Value of Ultrasonography (US) in Comparison with Only CT Imaging

PURPOSE: We aimed to assess retrospectively the benefit of the use of ultrasonography (US) in comparison with the use of only CT imaging for the detection of the transition zone and adhesions to determine a diagnosis of adhesive small-bowel obstruction (SBO). MATERIALS AND METHODS: Thirty-five patients underwent an additional US examination after CT imaging to determine a diagnosis of SBO. All of the patients were surgically confirmed as having adhesive SBO. The CT images were interpreted for the location of the transition zone, the location and shape of adhesions and for other SBO findings. All of the additional US scans were performed with reference to the CT findings. The standard of reference for the diagnosis was the surgical findings. The diagnostic accuracy and mean confidence score of the transition zone location and the detection rate of adhesions were evaluated for both CT imaging alone and for CT imaging with additional US. RESULTS: The diagnostic accuracy to locate the transition zone was significantly increased with the use of additional US with CT imaging (94.6%, 33/35) as compared to 65.7% (23/35) with the use of only CT imaging (p = 0.01). The mean confidence score was significantly increased (by 0.95) with the use of an additional US examination (p < 0.01). The detection rate for adhesions was 20% (7/35) with the use of only CT imaging and the detection rate was 68.6% (24/35) with the use of an additional US examination. CONCLUSION: The use of a US examination in addition to CT imaging can increase the accuracy and confidence to locate the transition zone and can increase the rate to detect adhesions in patients with adhesive SBO. An additional US examination may be especially helpful when the CT findings are equivocal.

Analysis of the Malignancy Rate for Thyroid Nodules based on the Use of a Fine Needle Aspiration Biopsy and Ultrasonography

PURPOSE: This study was designed to analyze the malignancy rate for thyroid nodules determined after a fine needle aspiration biopsy (FNAB) and ultrasonography (US) and to propose follow-up FNAB indications. MATERIALS AND METHODS: A total of 287 patients (265 female, 22 male) who underwent repeated US-guided FNABs were included in the cohort study. The results of the FNABs were classified as inadequate, benign, indeterminate, suspicious for a malignancy and a malignancy. The US findings were assigned five grades according to the possibility of a malignancy present. The frequency of a malignant nodule was evaluated by the use of the Kaplan-Meier method and Cox proportional risk model. RESULTS: The malignancy rates of inadequate, benign, and indeterminate nodules were 12.8%, 8.2% and 37.5%, respectively, for the FNAB findings. The rates of grades 3, 4 and 5 were 38.6%, 50.0% and 53.8%, respectively, for the US findings. Inadequate and indeterminate nodules as determined by an FNAB and grades 3, 4 and 5 assigned after US showed a higher malignancy rate than other nodules and would be regarded as high risk lesions. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 93.3%, 38.4%, 22.0%, 96.9% and 47.0%, respectively, if the nodule was considered a high-risk lesion, based on the FNAB or US findings. CONCLUSION: Thyroid nodules should be evaluated based on an FNAB and US findings. If a thyroid nodule is classified as a high-risk lesion, a follow-up study is needed due to the high malignancy rate.

An intraperitoneal tuberculous abscess: Computed tomography (CT) findings and clinical course / 대한내과학회지

BACKGROUND/AIMS: Intraperitoneal tuberculous abscesses develop infrequently. Because of overlapping features it is difficult to differentiate a tuberculous abscess from carcinomatosis peritonei. The aim of this study was to define the computed tomography (CT) findings and clinical course of the intraperitoneal tuberculous abscess. METHODS: The study included 11 patients (3 males, 8 females, mean age 34.8 years) with a pathologically proven intraperitoneal tuberculous abscess. We analyzed the CT findings and reviewed the medical records retrospectively. RESULTS: Sixteen abscesses were found in 11 patients. The locations of the abscesses were in the right subphrenic space (n=1), right perihepatic space (n=4), left perihepatic space (n=4), left subphrenic space (n=2), perisplenic space (n=3), right lower abdominal space (n=1), and left lower abdominal space (n=1). Five patients were proven to have abdominal tuberculosis while six patients had paradoxical responses to antituberculosis therapy for tuberculous peritonitis. The abscess lesions presented on the CT scan as thin walled cystic enhancing lesions without calcification (n=16), a septated mass (n=12), with enlargement of lymph nodes (n=2), and peritoneal and omental haziness (n=3). The mean duration from commencement of treatment to onset of a paradoxical response was 88 days. All patients had antituberculosis therapy for 6 to 12 months and five patients underwent surgery. The mean follow-up was 15 months. CONCLUSIONS: The intraperitoneal tuberculous abscess appeared as an ovoid cystic lesion with a slightly enhanced thin wall in the upper abdomen, in the perihepatic space on the CT scan; such as lesion can be the primary lesion of abdominal tuberculosis or associated with the paradoxical response of tuberculous peritonitis.

Localized Intrahepatic Bile Duct Dilatation without a Visible Mass or Stone as depicted on CT Images: Findings of Malignancy Prediction

PURPOSE: This study was performed to evaluate factors that can predict the presence of a malignancy for localized intrahepatic bile duct dilatation without a visible mass or stone as depicted on CT images. MATERIALS AND METHODS: A total of 29 patients (male: 16, female: 13) who had localized intrahepatic bile duct dilatation without a visible mass, stone or injury as depicted on CT images were included in the study. A history of extrahepatic malignancy and biliary stone disease, tumor marker levels, CT findings of the intrahepatic bile duct and associated findings were reviewed. The findings were analyzed between two groups (patients with a malignancy and patients with benign disease) on follow-up. RESULTS: In 29 patients, 11 patients had malignant lesions (four metastases and seven cholangiocarcinomas). The history of an extrahepatic malignancy and the shape of an intrahepatic duct obstruction or stenosis as seen on CT were significantly correlated with the results between the benign and malignant group of patients. The follow-up results of the malignant group of patients indicated that for six patients who had developed a new mass, one patient each showed aggravation of ductal dilatation and thickening of the ductal wall. CONCLUSION: When a patient with localized intrahepatic bile duct dilatation without a definite cause has a history of an extrahepatic malignancy or shows abrupt tapering or irregular narrowing on CT images, short-term follow-up should be performed. The patient should be investigated carefully for mass formation or a change of the dilated bile duct due to a possibility of malignant ductal dilatation.

Current Status of Clinical Image Evaluation of Mammograms: Preliminary Report

PURPOSE: To survey the current overall quality of mammograms and to improve Korean standards in comparison to the American College of Radiology (ACR) standards for clinical image evaluations. MATERIALS AND METHODS: A total of 104 mammograms, collected from 63 hospitals and clinics, were examined following the revised new Korean standards and ACR standards for clinical image evaluation. The pass and failure rates of the mammogram were evaluated according to each of the standards compared. The pass threshold for the Korean standards was analyzed using the ROC (receiver operating characteristic) curve in association with the ACR standards. The categories of the Korean standards were evaluated in association with failure of the ACR standards. RESULTS: Among the 104 mammograms, 99.0% passed the Korean standards, whereas 86.5% passed the ACR standards. A score of 75.5 was the pass threshold for the Korean standards. Moreover, the Korean standards categories associated with the failure of ACR standards included positioning, compression, and contrast/exposure (p < 0.05). CONCLUSION: The pass rate of the image evaluation for each mammogram following the Korean standards was 99%, compared to 86.5% for the ACR standards. Hence, the Korean standards were not as stringent. Consequently, stricter regulations are suggested for improvement in the quality of mammograms.

Comparison of in Vivo, in Vitro 3T MR Spectroscopy and Proton NMR Spectroscopy for the Fluid from Cystic Tumor: Preliminary Study

PURPOSE: The aim of this study is to determine possibility of application of in vivo proton (1H) magnetic resonance spectroscopy (MRS) in distinguishing cystic mass arising around pancreas by comparison of in vivo MRS, in vitro MRS using 3T MR machine, based on nuclear magnetic resonance (NMR). MATERIALS AND METHODS: We obtained spectra of in vivo MRS, in vitro MRS and NMR from abdominal mass arising around pancreas (mucinous cystic neoplasm=5, intraductal papillary mucin producing tumor=5, pseudocyst=1, and lymphangioma=1). We estimated existence of peak of in vivo MRS, and in vitro MRS concordant to that of NMR. We also evaluated differential peak for predicting specific disease. RESULTS: Correlation of presence of peak with NMR showed showed sensitivity of 29.6%, specificity of 82.6% and accuracy of 67.7% on in vivo MRS (p = 0.096, McNemar test), sensitivity of 57.1% and specificity of 92.6% and accuracy of 82.3% on in vitro MRS (p = 0.362, McNemar test). The spectra of NMR for IPMT showed more frequent peaks at 3.5-4.0 ppm (p=0.026). CONCLUSION: Although chemical analysis, using NMR could be regarded as possible tool to differentiate cystic masses, in vivo and in vitro MRS need further technical evolution for clinical application.