Left-Side Contrast-Injection-Induced Pseudopathologic Vertebral Enhancement in Oncology Patients without Venous Obstruction: A Report of Two Cases.

The appearance of sclerotic bone lesions in contrast-enhanced computed tomography (CT) scans is often a significant concern for the possible presence of metastatic disease, especially in individuals with a known history of cancer. Prior research has demonstrated that in cases where patients suffer from thrombosis in major veins like the superior vena cava or the brachiocephalic vein, vertebral venous congestion can create imaging patterns on CT scans that resemble sclerotic bone metastases. However, instances of such imaging findings in patients without any form of venous obstruction are not commonly reported. In this study, we present cases of pseudopathologic vertebral enhancement observed consistently following left-side contrast injections in cancer patients devoid of venous obstruction. We aim to discuss and propose a potential mechanism for this phenomenon, drawing attention to a less commonly recognized diagnostic consideration in oncological imaging.

Airspace Enlargement with Fibrosis in a Young Heavy Smoker Mimicking Diffuse Cystic Lung Disease.

The widespread use of computed tomography (CT) has led to the increased recognition of cystic lung lesions. Multiple pulmonary cysts can be observed in heterogeneous disorders called diffuse cystic lung diseases (DCLDs), which include pulmonary Langerhans cell histiocytosis, lymphangioleiomyomatosis, lymphocytic interstitial pneumonia, and Birt-Hogg-Dubé syndrome. Recently, airspace enlargement with fibrosis (AEF) has been recognized as an entity on the spectrum of smoking-related lung diseases. We report a young male heavy smoker presenting diffuse pulmonary cysts on chest CT with suspected DCLD. However, histopathological examination of the surgical biopsy specimen revealed dilated emphysematous cysts with prominent mural fibrosis, consistent with AEF.

Transcatheter Arterial Embolization for Spontaneous Hepatic Rupture Associated with HELLP Syndrome: A Case Report.

Background: Spontaneous hepatic rupture associated with the syndrome characterized by hemolysis, elevated liver enzymes, and a low platelet count (HELLP syndrome) is a rare and life-threatening condition, and only a few cases regarding the management of this condition through transcatheter arterial embolization (TAE) have been previously reported. Case summary: Herein, we report a case involving a 35-year-old pregnant woman who presented at 28 weeks of gestation with right upper quadrant pain, hypotension, and elevated levels of liver enzymes. Transabdominal ultrasound revealed fetal death. She required an emergency cesarean section, and hepatic rupture was identified after the fetus had been delivered. Hepatic packing and TAE were performed. The postprocedural course was uneventful, and the patient was discharged 14 days after she had been admitted to our hospital. Conclusions: Spontaneous hepatic rupture associated with HELLP syndrome is a very serious condition that requires prompt and decisive management. The high maternal and fetal mortality rates associated with this condition can be reduced through early accurate diagnosis and adequate management. The findings in the reported case indicate that TAE may be an attractive alternative to surgery for the management of spontaneous hepatic rupture associated with HELLP syndrome.

Correction to: T1 mapping for liver function evaluation in gadoxetic acid-enhanced MR imaging: comparison of look-locker inversion recovery and B1 inhomogeneity-corrected variable flip angle method.

The original version of this article, published on 22 March 2019, unfortunately contained a mistake. The following correction has therefore been made in the original: Affiliations 1 and 2 were presented incorrectly.

Respiratory motion-resolved four-dimensional zero echo time (4D ZTE) lung MRI using retrospective soft gating: feasibility and image quality compared with 3D ZTE.

OBJECTIVES: To evaluate the feasibility and image quality of respiratory motion-resolved 4D zero echo time (ZTE) lung MRI compared with that of 3D ZTE. METHODS: Our institutional review board approved this study. Twenty-one patients underwent lung scans using 3D ZTE and 4D ZTE sequences via prospective and retrospective soft gating techniques, respectively. Image qualities of 3D ZTE and 4D ZTE at end-expiration were compared through objective and subjective assessments. The quality of end-expiratory images of 3D ZTE and 4D ZTE of the two groups with different lung functions was also compared. RESULTS: Images were successfully acquired in all patients without any adverse events. Signal-to-noise ratios (SNRs) of lung parenchyma and thoracic structures were significantly (all p < 0.001) higher in 4D ZTE. Contrast-to-noise ratios (CNRs) of peripheral bronchi, peripheral pulmonary vessels, and nodules or masses were significantly (all p < 0.001) higher in 4D ZTE. The subjective image quality assessed by two independent radiologists showed that intrapulmonary structures, noise and artifacts, and overall acceptability were superior in 4D ZTE (all p < 0.001). Image qualities of groups with normal and low lung functions differed significantly (all p < 0.05) in 3D ZTE, but not in 4D ZTE. The mean acquisition time was 136 s (127-143 s) in 3D ZTE and 325 s (308-352 s) in 4D ZTE. CONCLUSIONS: Respiratory motion-resolved 4D ZTE lung imaging was feasible as part of routine chest MRI. The 4D ZTE provides motion-robust lung parenchymal images with better SNR and CNR than the 3D ZTE, regardless of patients' lung function. KEY POINTS: • ZTE MRI captures rapidly decaying transverse magnetization in the lung parenchyma. • 4D ZTE provides motion-robust lung parenchymal images with better SNR and CNR compared with 3D ZTE. • Compared with 3D ZTE, the image quality of 4D ZTE lung MRI was affected less by patients' lung function and respiratory performance.

Quantification of liver extracellular volume using dual-energy CT: utility for prediction of liver-related events in cirrhosis.

OBJECTIVES: To determine whether quantification of liver extracellular volume fraction (fECV) using dual-energy CT (DECT) allows prediction of liver-related events (LREs) in cirrhotic patients. METHODS: This retrospective study included 305 cirrhotic patients who underwent dual-source DECT imaging and had serum markers analyzed within 2 weeks of initial CT imaging. The fECV score was measured using an iodine map of equilibrium-phase images obtained 3 min after contrast injection at 100/140 Sn kVp. The association of the fECV score and serum markers with LREs was investigated. A risk model combining the fECV score (< 27 versus ≥ 27%) and serum albumin level (< 4 versus ≥ 4 g/dL) was constructed for LRE prediction. RESULTS: An increased fECV score (odds ratio, 1.27; 95% confidence interval (CI), 1.15, 1.40) was independently associated with decompensated cirrhosis at baseline (n = 85) along with the Model for End-Stage Liver Disease score (odds ratio, 1.32; 95% CI, 1.07, 1.63). Among patients with compensated cirrhosis, 10.5% (23 of 220) experienced LREs during the median follow-up period of 2.0 years (decompensation, n = 14; hepatocellular carcinoma, n = 9). The fECV score (hazard ratio, 1.40; 95% CI, 1.22, 1.62) and serum albumin level (hazard ratio, 0.26; 95% CI, 0.09, 0.73) were independent predictors of LRE. The mean times to LRE among the high (16.5 months, n = 18)-, intermediate (25.6 months, n = 44)-, and low (30.5 months, n = 158)-risk groups were significantly different (p < 0.001). CONCLUSIONS: The fECV score derived from DECT allows prediction of LREs in cirrhotic patients. KEY POINTS: • The extracellular volume fraction (fECV) score derived from the iodine map of dual-energy CT (DECT) was independently associated with the presence of hepatic decompensation. • The fECV score derived from the iodine map of DECT can predict liver-related events (LREs) in patients with cirrhosis. • Equilibrium-phase scanning in dual-energy mode is recommended as part of liver CT in cirrhotic patients because it can provide a prognostic indicator for LRE development.

Initial clinical experience of synthetic MRI as a routine neuroimaging protocol in daily practice: A single-center study.

BACKGROUND AND PURPOSE: We investigated the clinical feasibility of synthetic MRI with a 4-min single scan using a 48-channel head coil as a routine neuroimaging protocol in daily practice by assessing its diagnostic image quality. METHODS: We retrospectively reviewed the imaging data of 89 patients who underwent routine brain MRI using synthetic MRI acquisition between February 2017 and April 2017. Image quality assessments were performed by two independent readers on synthetic T1 fluid-attenuated inversion recovery (FLAIR), T2-weighted, T2 FLAIR, and phase-sensitive inversion recovery sequences acquired using multiple-dynamic multiple-echo imaging. Interobserver reliability between the two readers was assessed using kappa (κ) statistics. RESULTS: On a 4-point assessment scale, the overall image quality and anatomical delineation provided by synthetic brain MRI were found to be good with scores of more than 3 points for all sequences except for the T2 FLAIR sequence. The synthetic T2 FLAIR sequence provided sufficient image quality but showed more pronounced artifacts, especially the CSF pulsation artifact and linear hyperintensity along the brain surface. Interobserver agreement for evaluating image quality of all synthetic sequences was good to excellent (κ, 0.61-0.99; P < 0.001). CONCLUSION: Synthetic MRI can be acceptable as a routine clinical neuroimaging protocol with a short scan time. It can be helpful to design customized and flexible neuroimaging protocols for each institution.

T1 mapping for liver function evaluation in gadoxetic acid-enhanced MR imaging: comparison of look-locker inversion recovery and B1 inhomogeneity-corrected variable flip angle method.

OBJECTIVES: To compare look-locker inversion recovery (LLIR) and B1 inhomogeneity-corrected variable flip angle T1 mapping methods for estimation of liver function and prediction of hepatic insufficiency and decompensation on gadoxetic acid-enhanced MR imaging. METHODS: In this retrospective study, 248 patients with normal liver function, chronic liver disease, or cirrhosis underwent gadoxetic acid-enhanced liver MR imaging, including T1 mapping at 10-min and 20-min hepatobiliary phase (HBP) by using both methods. T1 relaxation times of the liver (T1Liver-pre, T1Liver-post) and the spleen (T1Spleen) were correlated between two methods. ΔT1Liver ([T1Liver-pre - T1Liver-post]/T1Liver-pre), adjusted T1Liver ([T1Spleen - T1Liver-post]/T1Spleen), and functional liver volume-to-weight ratio (liver volume on volumetric T1 map/[T1Liver-post × patient's weight]) were calculated. The diagnostic performance of T1 parameters and the predictive performance of models (serum marker, serum marker plus T1 parameter) were compared. RESULTS: T1Liver-post showed a strong correlation (r = 0.93, p < 0.001) between two methods but was significantly different. For depicting cirrhosis, LLIR-adjusted T1Liver at 10-min HBP showed the highest performance (p < 0.025). For predicting hepatic insufficiency and decompensation, LLIR-adjusted T1Liver (Akaike information criterion (AIC), 58.37; C-index, 0.867) and LLIR-T1Liver-post (AIC, 48.82; C-index, 0.885) at 10-min HBP showed the best performance, respectively, when added to serum albumin level. CONCLUSIONS: T1Liver-post showed a strong correlation between two methods but with significant differences. T1 mapping using LLIR at 10-min HBP with obtainment of adjusted T1Liver and T1Liver-post may be the best approach for estimation of liver function and prediction of hepatic insufficiency and decompensation. KEY POINTS: • T1 Liver-post showed a strong correlation between LLIR and B 1 inhomogeneity-corrected VFA methods, both at 10-min and 20-min HBP but with significant differences. • T1 Liver-post at 10-min and 20-min HBP using LLIR and B 1 inhomogeneity-corrected VFA methods could not be used interchangeably during the follow-up in patients with chronic liver disease (CLD) or cirrhosis. • T1 mapping using LLIR at 10-min HBP with obtainment of adjusted T1 Liver and T1 Liver-post may be the most suitable method and parameter for estimation of global liver function and prediction of clinical outcomes in patients with CLD or cirrhosis.

Comparison of lung imaging using three-dimensional ultrashort echo time and zero echo time sequences: preliminary study.

OBJECTIVE: To determine the feasibility of using high-resolution volumetric zero echo time (ZTE) sequence in routine lung magnetic resonance imaging (MRI) and compare free breathing 3D ultrashort echo time (UTE) and ZTE lung MRI in terms of image quality and small-nodule detection. MATERIALS AND METHODS: Our Institutional Review Board approved this study. Twenty patients underwent both UTE and ZTE sequences during routine lung MR. UTE and ZTE images were compared in terms of subjective image quality and detection of lung parenchymal signal, intrapulmonary structures, and sub-centimeter nodules. Differences between the two sequences were compared through statistical analysis. RESULTS: Lung parenchyma showed significantly (p < 0.05) higher signal-to-noise ratio (SNR) in ZTE than in UTE. The SNR and contrast-to-noise ratio (CNR) of peripheral bronchus and small pulmonary arteries were significantly (all p < 0.05) higher in ZTE. Subjective image quality evaluated by two independent radiologists in terms of depicting normal structures and overall acceptability was superior in ZTE (p < 0.05). The diagnostic accuracy for sub-centimeter nodules was significantly higher for ZTE (reader 1: AUC, 0.972; p = 0.044; reader 2: AUC, 0.946; p = 0.045) than that for UTE (reader 1: AUC, 0.885; reader 2: AUC, 0.855). Mean scan time was 131 s (125-141 s) in ZTE and 467 s (453-508 s) in UTE. ZTE images were obtained with less acoustic noise. CONCLUSION: Implementing ZTE as an additional sequence in routine lung MR is feasible. ZTE can provide high-resolution pulmonary structural information with better SNR and CNR using shorter time than UTE. KEY POINTS: • Both UTE and ZTE techniques use very short TEs to capture signals from very short T2/T2* tissues. • ZTE is superior in capturing lung parenchymal signal than UTE. • ZTE provides high-resolution structural information with better SNR and CNR for normal intrapulmonary structures and small nodules using shorter scan time than UTE.

Improved Opacification of a Suboptimally Enhanced Pulmonary Artery in Chest CT: Experience Using a Dual-Layer Detector Spectral CT.

OBJECTIVE: The objective of our study was to evaluate the quality of virtual monoenergetic imaging (VMI) from dual-layer detector spectral CT and the effect of virtual monoenergetic images obtained at low energies on the detection of pulmonary embolism (PE) in patients with a suboptimally enhanced pulmonary artery on chest CT. MATERIALS AND METHODS: Of 1552 consecutive chest CT examinations performed with dual-layer detector spectral CT using a routine protocol with a tube voltage of 120 kVp, 79 examinations with suboptimal enhancement of the pulmonary artery (i.e., mean attenuation of pulmonary artery ≤ 180 HU) were included. The mean attenuation of the pulmonary artery, noise, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) of virtual monoenergetic images obtained at 40-200 keV were compared with those of the conventional 120-kVp images. The virtual monoenergetic images with the best CNR were compared with the 120-kVp images with regard to subjective image quality and diagnostic accuracy for detecting PE. RESULTS: Sufficient attenuation of the pulmonary artery (> 180 HU) was obtained using VMI for 78 of the 79 examinations. The noise levels of the virtual monoenergetic images were gradually increased with decreasing energy level (i.e., kiloelectron volt setting). The CNR and SNR of virtual monoenergetic images at 40-65 keV were significantly higher (both, p < 0.001) than the CNR and SNR of the 120-kVp images. The CNR was the highest at 40 keV for all cases. Diagnostic accuracy for detecting PE was significantly higher for 40-keV images (reader 1: AUC = 0.992, p = 0.033; reader 2: AUC = 0.986, p = 0.043) than for 120-kVp images (reader 1, AUC = 0.911; reader 2, AUC = 0.933). The subjective quality was not different between these two images. CONCLUSION: In chest CT examinations in which the pulmonary artery is suboptimally enhanced, obtaining virtual monoenergetic images at a low energy setting using dual-layer detector spectral CT allows sufficient attenuation of the pulmonary artery to be achieved while preserving image quality and increasing diagnostic performance for detecting PE.

Added value of point shear-wave elastography in the diagnosis of acute cholecystitis.

OBJECTIVE: To evaluate the added value of point shear-wave elastography (pSWE) in the diagnostic performance of conventional US for diagnosis of acute cholecystitis. METHODS: B-mode and colour Doppler US and pSWE were performed prospectively in 216 patients with clinically suspected acute cholecystitis. The morphology and mural vascularity of the gallbladder and median shear wave velocity (SWV) of the right liver were evaluated. Two observers independently reviewed conventional US images and subsequently reviewed combined conventional US and pSWE images. RESULTS: Mean SWVs of the acute cholecystitis group (n = 91) were significantly higher than those of the control group (n = 85) in the right liver within 2 cm lateral to the gallbladder (1.56 versus 1.03 m/s, 1.39 versus 1.04 m/s, P < 0.0001) with a cut-off value of 1.29 or 1.16 m/s. The area under the receiver operating characteristic curve of both observers in the diagnosis of acute cholecystitis improved significantly from 0.790 and 0.777 to 0.963 and 0.962, respectively, after additional review of pSWE images (P < 0.0001). Diagnostic accuracy, sensitivity, specificity, positive and negative predictive values of combined image sets were higher than those of conventional US images alone. CONCLUSION: Adding pSWE to conventional US improves the diagnosis of acute cholecystitis when compared with conventional US alone. KEY POINTS: • In acute cholecystitis, stiffness of the right liver increases adjacent to the gallbladder. • The cut-off value for diagnosing acute cholecystitis was 1.29 or 1.16 m/s. • Adding pSWE to conventional US improves the diagnosis of acute cholecystitis.

Interpretations of diffusion-weighted MR imaging by radiology residents in the emergency department: is diagnostic performance influenced by the level of residency training?

BACKGROUND: To evaluate the diagnostic performance of radiology residents' interpretations for diffusion-weighted MR imaging (DWI) in the emergency department at different levels of residency training. METHOD AND MATERIALS: A total of 160 patients who underwent DWI with acute neurologic symptoms were included in this retrospective study with an institutional review board approval. Four radiology residents with different training years and one attending neuroradiologist independently assessed the DWI results. Discordances between the results of residents and attending neuroradiologist were classified as follows: false positive (FP) and false negative (FN). We also evaluated the diagnostic performance of four residents according to the reference standard. RESULTS: Overall, the concordance rate was 84.8 %, with a 15.2 % overall discordance rate. There were 83 FN results. The most common misses were small vessel disease (n = 55), acute focal infarction (n = 10), diffuse axonal injury (n = 6), solitary mass (n = 5), extraaxial hemorrhages (n = 3), posterior reversible encephalopathy syndrome (n = 2), and postictal change (n = 2). Fourteen FP results were interpreted as hemorrhage and acute infarction. The 4th year resident exhibited the highest diagnostic performance, and the level of training had a significant influence on the rates of concordance (P < 0.05). Interobserver reliability was good between the interpretations of the residents and the final interpretations of the attending neuroradiologists. CONCLUSION: The level of resident training had a significant effect on their diagnostic performance, and good interobserver reliability was noted between the results of the residents and attending neuroradiologist.

Pulmonary Tuberculosis in Patients With Emphysema: Computed Tomography Findings.

OBJECTIVE: To evaluate the computed tomography (CT) findings and clinical characteristics of pulmonary tuberculosis (TB) in patients with emphysema, compared with those without emphysema. MATERIALS AND METHODS: Thirty-nine patients (M:F = 36:3; mean age, 64.8 years) who were diagnosed with chronic obstructive pulmonary disease and had emphysema in pretreatment chest CT scans were included in this study (emphysema group). Their clinical presentation, laboratory findings, and CT findings were compared with those of 57 pulmonary TB patients without chronic obstructive pulmonary disease and emphysema (M:F = 52:5; mean age, 64.3 years) (nonemphysema group). RESULTS: Fever was a more frequent clinical presentation and the C-reactive protein level was higher in the emphysema group. Among CT findings, consolidation and ground-glass opacity were seen more frequently in the emphysema group (82% and 69% vs 42% and 19%, respectively, P < 0.001). Consolidation was more often nonsegmental than lobular or segmental. Tree-in-bud appearance was less frequently noted in the emphysema group (36% vs 79%, P < 0.001). The location of main lesions (upper lung vs middle/lower lung) was not different between the 2 groups. CONCLUSIONS: Pulmonary TB in emphysema patients often shows bacterial pneumonia-like features, that is, presence of consolidation and ground-glass opacity and lack of bronchogenic spread on chest CT scans, combined with the presence of fever and a high C-reactive protein level. Sputum smear for acid-fast bacteria should be performed early in emphysema patients with pneumonia in TB-endemic areas.

Novel methodology to evaluate renal cysts in polycystic kidney disease.

AIM: To develop and assess a semiautomated method for segmenting and counting individual renal cysts from mid-slice MR images in patients with autosomal dominant polycystic kidney disease (ADPKD). METHODS: A semiautomated method was developed to segment and count individual renal cysts from mid-slice MR images in 241 subjects with ADPKD from the Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease. For each subject, a mid-slice MR image was selected from each set of coronal T2-weighted MR images covering the entire kidney. The selected mid-slice image was processed with the semiautomated method to segment and count individual renal cysts. The number of cysts from the mid-slice image of each kidney was also measured by manual counting. The level of agreement between the semiautomated and manual cyst counts was compared using intraclass correlation (ICC) and a Bland-Altman plot. RESULTS: Individual renal cysts were successfully segmented using the semiautomated method in all 241 cases. The number of cysts in each kidney measured with the semiautomated and manual counting methods correlated well (ICC = 0.96 for the right or left kidney), with a small average difference (-0.52, with higher semiautomated counts, for the right kidney, and 0.13, with higher manual counts, for the left kidney) in the semiautomated method. However, there was substantial variation in a small number of subjects; 6 of 241 participants (2.5%) had a difference in the total cyst count of more than 15. CONCLUSION: We have developed a semiautomated method to segment individual renal cysts from mid-slice MR images in ADPKD kidneys as a quantitative indicator of characterization and disease progression of ADPKD.

Fish bone foreign bodies in the pharynx and upper esophagus: evaluation with 64-slice MDCT.

BACKGROUND: Fish bone (FB) is one of the common causes of foreign body impaction in the pharynx and esophagus. PURPOSE: To investigate the efficacy of 64-slice multidetector computed tomography (MDCT) for the evaluation of pharynx and upper esophageal FB foreign bodies. MATERIAL AND METHODS: Sixty-six patients with suspected FB foreign body ingestion were examined by plain radiography (n = 40) and unenhanced MDCT (n = 66). We analyzed the presence, location, size, shape, and lying position of the foreign bodies. RESULTS: On MDCT, 46 foreign bodies were detected. Among them, 45 were confirmed by endoscopy. The sensitivity of MDCT for the detection of foreign bodies was 100%, which was superior to that of the plain radiography (51.7%). The location of the foreign bodies was most common in the upper esophagus (n = 22, 47.8%), followed by pharyngoesophageal junction (n = 10, 21.7%), transjunctional (n = 7, 15.2%), hypopharynx (n = 5, 10.9%), and oropharynx (n = 2, 4.3%). Their longest length was 5.3-40.1 mm (mean, 21.3 mm). Thirty-three FBs (71.7%) were linear and 13 (28.3%) were flat in shape. They showed transverse (n = 23, 50.0%), parallel (n = 13, 28.3%), and oblique positions (n = 10, 21.7%) to the long axis of the pharynx and esophagus, respectively. CONCLUSION: MDCT is useful for the evaluation of the pharynx and upper esophageal FB foreign bodies.

US-guided transthoracic biopsy of peripheral lung lesions: pleural contact length influences diagnostic yield.

BACKGROUND: Transthoracic biopsy of peripheral lung lesions under ultrasonography (US) guidance is a useful diagnostic technique. However, factors affecting diagnostic yield of US-guided transthoracic biopsy of peripheral lung lesions are not well established. PURPOSE: To determine the factors that influence diagnostic yield of US-guided transthoracic biopsy in peripheral lung lesions. MATERIAL AND METHODS: A total of 100 consecutive patients underwent US-guided percutaneous cutting biopsy of peripheral lung lesions from October 2007 to March 2009. After seven unconfirmed cases were excluded, 97 procedures in 93 consecutive patients were included in this study. The accuracy of the lung biopsies was assessed by comparing the biopsy results with the final diagnoses. We divided the cases into a correct group (true-positive and true-negative) and an incorrect group (false-positive, false-negative, and non-diagnostic results) and analyzed the differences in the lesions, procedures, and patient variables between the two groups. RESULTS: According to the final diagnoses, 56 cases (57.7%) were malignant and 41 cases (42.3%) were benign. An overall diagnostic accuracy of 91.8% was obtained. The median size of the lesions was 46.0 mm (interquartile range [IQR], 30.0-69.5 mm), and the median lesion-pleura contact arc length (LPCAL) was 31.0 mm (IQR, 18.0-51.0 mm). Multivariate logistic regression analysis showed that only LPCAL (odds ratio, 1.16; 95% CI, 1.04-1.30) was a significant predictor of a correct diagnosis. When we divided the lesions into those with LPCAL values >30 mm and LPCAL values ≤30 mm, the sensitivity (96.6% vs. 74.1%; P = 0.02) and the accuracy (98% vs. 85.4%; P = 0.03) were significantly higher in the group with larger LPCAL. CONCLUSION: In US-guided transthoracic biopsy of peripheral lung lesions, the LPCAL of the lesions is an important factor for a correct diagnosis.

Added value of 40 keV virtual monoenergetic images for diagnosing malignant pleural effusion on chest CT.

OBJECTIVE: This study aimed to evaluate the added value of 40 keV virtual mono-energetic images (VMIs) obtained from dual-layer detector CT (DLCT) for diagnosing malignant pleural effusion (MPE) in patients presenting with unilateral pleural effusion on chest CT. MATERIALS AND METHODS: This retrospective study included 75 patients with unilateral pleural effusion who underwent contrast-enhanced chest CT scans using DLCT. Quantitative and qualitative assessments of the visibility of pleural thickening were conducted on both conventional 120 kVp images and 40 keV VMIs. Two independent radiologists reviewed chest CT scans with or without 40 keV VMIs to detect pleural nodules or nodular thickening for the diagnosis of MPE. Diagnostic performances were compared and independent predictors of MPE were identified through multivariate logistic regression analysis using CT and clinicopathologic findings. RESULTS: Pleural thickening associated with MPE demonstrated a higher contrast-to-noise ratio value and greater visual conspicuity in 40 keV VMIs compared to benign effusions (p < 0.05). For both readers, the use of 40 keV VMIs significantly improved (p < 0.05) the diagnostic performance in terms of sensitivity and area under the curve (AUC) for diagnosing MPE through the detection of pleural nodularity. Inter-observer agreements between the two readers were substantial for both 120 kVp images alone and the combined use of 40 keV VMIs. Initial cytology results and pleural nodularity at 40 keV were identified as independent predictors of MPE. CONCLUSION: The use of 40 keV VMIs from DLCT can improve diagnostic performance of readers in detecting MPE among patients with unilateral pleural effusion.

Left Bronchial Isomerism with Right-Sided Tracheal Bronchus: A Rare Case Report.

The tracheal bronchus is a congenital bronchial branching anomaly defined as an aberrant bronchus arising in either the trachea or a main bronchus. Left bronchial isomerism is characterized by two bilobed lungs, bilateral long main bronchi, and both pulmonary arteries passing superiorly to their respective upper lobe bronchi. Left bronchial isomerism with a right-sided tracheal bronchus is a very rare combination of tracheobronchial anomalies. It has not been previously reported. We present multi-detector CT findings of a left bronchial isomerism with a right-sided tracheal bronchus of a 74 year old man.

High-Grade Surface Osteosarcoma of the Rib Mimicking a Neurogenic Tumor: Radiologic and Pathologic Findings.

Osteosarcoma commonly occurs in the intramedullary cavity of long bones such as the femur, tibia, and humerus in children and adolescents. Osteosarcoma occurring as a primary tumor in the chest wall is rare. Only a limited number of such cases have been documented in the existing literature. Herein, we present radiologic and pathologic findings of a high-grade surface osteosarcoma of the rib mimicking a neurogenic tumor in a 44-year-old woman.

Kikuchi-Fujimoto Disease in the Axilla after COVID-19 Vaccination: A Case Report.

BACKGROUND: Kikuchi-Fujimoto disease (KFD) is a rare, self-limiting inflammatory condition of unknown etiology that is characterized by fever and painful lymphadenopathy. KFD commonly involves the posterior cervical region and very rarely occurs in the axilla. CASE PRESENTATION: We report on a case of KFD that presented 3 weeks after receiving the messenger ribonucleic acid-based coronavirus disease 2019 (COVID-19) vaccine. In this case, we suspected the lesions as COVID-19 vaccination-related lymphadenopathy on the initial ultrasonographic examination. CONCLUSION: Through this case report, we highlight that KFD should be considered in the differential diagnosis of patients with axillary lymphadenopathy who have undergone COVID-19 vaccination, as unusual side effects of COVID-19 vaccination have been increasingly reported in the literature owing to the rapid development of various COVID-19 vaccines during the pandemic period. In addition, we emphasize the importance of clinical suspicion in diagnosing KFD due to the fact that axillary involvement of KFD is extremely rare.