Substitution with Low-Osmolar Iodinated Contrast Agent to Minimize Recurrent Immediate Hypersensitivity Reaction.

Background The recurrence of hypersensitivity reaction (HSR) to low-osmolar iodinated contrast media (LOCM) remains challenging despite premedication and substitution of the LOCM. Purpose To determine the optimal practical preventive strategy for LOCM substitution in patients with a history of prior immediate HSR to LOCM. Materials and Methods In a retrospective study, patients with an immediate HSR to LOCM before February 2020 and who underwent subsequent exposure to LOCM until March 2021 were enrolled in five tertiary referral hospitals in South Korea. The association of recurrence of an HSR after subsequent LOCM exposures was assessed using multivariate general estimating equation analysis according to age, sex, the severity of the index HSR, premedication, and substituting LOCM based on common carbamoyl side chains, including the N-(2,3-dihydroxypropyl)-carbamoyl and N-(2,3-dihydroxypropyl)-N-methyl-carbamoyl moieties. Results The evaluation included 3800 subsequent LOCM exposures in 1066 patients (mean age, 56.2 years ± 13.5 [SD]; 567 [53%] female and 499 [47%] male patients). The general estimating equation analysis, using 1:1 propensity score matched data for age, sex, HSR severity, and LOCM selection, showed that premedication with corticosteroids significantly reduced recurrent HSR (odds ratio [OR], 0.72; 95% CI: 0.52, 1.00; P = .049). The change to another LOCM with a common side chain had a similar recurrence rate as using the same LOCM (OR, 0.98; 95% CI: 0.64, 1.50; P = .93), whereas the use of a different LOCM without a common side chain significantly lowered HSR recurrence (OR, 0.51; 95% CI: 0.37, 0.69; P < .001) in multivariate general estimating equation analysis. Substitution of an LOCM without a common side chain was effective regardless of the index HSR severity but was more pronounced in moderate-to-severe reactions (OR, 0.30; 95% CI: 0.16, 0.55; P < .001). Conclusion For patients with a previous immediate HSR of any severity to LOCM, alternative LOCM without a common carbamoyl side chain reduced recurrent HSR during subsequent exposures. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by McDonald in this issue.

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.

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.

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.

Hypersensitivity Reactions to Iodinated Contrast Media: A Multicenter Study of 196 081 Patients.

Background Multicenter studies may be required for establishing guidelines for safe usage of iodinated contrast media (ICM). Purpose To identify the prevalence, patterns, risk factors, and preventive measures for ICM-related hypersensitivity reactions (HSRs). Materials and Methods Between March 2017 and October 2017, a total of 196 081 patients who underwent ICM administration were enrolled from seven participating institutions. The occurrence of HSRs and baseline patient information were recorded. χ2 and Student t test were performed, and logistic regression analyses were used to identify risk factors that predict occurrence and recurrence of HSR. Results Among 196 081 patients (mean age ± standard deviation, 59.1 years ± 16.0; 105 014 men and 91 067 women) who underwent ICM administration, the overall prevalence of HSRs was 0.73% (1433 of 196 081), and severe reactions occurred in 0.01% (17 of 196 081). Conditional logistic regression for patients with HSR (n = 1433) and a control group (1:1 matched group for age, sex, ICM product, and institution) demonstrated that a patient's previous individual history of an ICM-related HSR (adjusted odds ratio [OR], 198.8; P < .001), hyperthyroidism (adjusted OR, 3.6; P = .04), drug allergy (adjusted OR, 3.5; P < .001), and other allergic diseases (adjusted OR, 6.8; P < .001) and a family history of ICM-related HSRs (adjusted OR, 14.0; P = .01) were predictors of HSR occurrence. Logistic regression analysis showed that use of premedication with antihistamine (OR, 0.5; P = .01) and change in the generic profile of ICM (OR, 0.5; P < .001) were preventive against recurrent HSR. Conclusion Family history as well as previous individual history of hypersensitivity reactions (HSRs) to iodinated contrast media (ICM) were risk factors for HSR occurrence, suggesting a potential genetic predisposition. A change in the culprit ICM and premedication with antihistamine are useful for reducing the recurrence of HSRs. © RSNA, 2019 Online supplemental material is available for this article.

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.

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.

Sarcopenia and inflammation are independent predictors of survival in male patients newly diagnosed with small cell lung cancer.

PURPOSE: Sarcopenia is suggested to be associated with cancer-related inflammation. We assessed the clinical outcome of small cell lung cancer (SCLC) patients according to sarcopenia and the neutrophil-to-lymphocyte ratio (NLR). METHODS: A total of 117 male SCLC patients treated with first-line chemo- or chemoradiotherapy were assessed based on a retrospective chart review. The mass of the pectoralis muscle was measured by computed tomography and normalized to height. Patients with the lowest quartile of muscle mass were considered to have sarcopenia. Patients were classified into four groups according to their sarcopenia and NLR statuses: sarcopenia/high NLR, sarcopenia/low NLR, non-sarcopenia/high NLR, and non-sarcopenia/low NLR. RESULTS: Sarcopenic patients had lower progression-free survival (PFS) than did non-sarcopenic patients (median 6.0 vs. 7.5 months, p = 0.009), but the difference in overall survival (OS) was not statistically significant (median 10.5 vs. 13.5 months, p = 0.052). However, the OS of sarcopenic patients with high NLR was significantly lower than that in all other groups (median 3.2 vs. 16.0 vs. 12.5 vs. 13.7 months, respectively, p < 0.001), as was PFS (median 3.2 vs. 7.7 vs. 7.6 vs. 7.1 months, respectively, p < 0.001). On multivariate analysis, sarcopenia with high NLR was an independent prognostic factor for shorter PFS and OS. Early discontinuation of treatment (20.0 vs. 10.3 %) and treatment-related mortality (50.0 vs. 8.4 %) occurred more frequently in these patients than in the other groups (p < 0.001). CONCLUSIONS: In SCLC, sarcopenic male patients with high NLR have a poor prognosis and do not tolerate standard treatment. Intensive supportive care is needed in these patients.

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.

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.

The rate of resolution of clot burden measured by pulmonary CT angiography in patients with acute pulmonary embolism.

OBJECTIVE: The purpose of this article is to quantitatively assess the rate of resolution of clot burden detected on pulmonary CT angiography (CTA) in patients with acute pulmonary embolism (PE). MATERIALS AND METHODS: We evaluated 111 consecutive patients (55 men and 56 women) in a retrospective cohort who were diagnosed with PE by pulmonary CTA and had at least one follow-up pulmonary CTA within 1 year. Two radiologists in consensus measured the volume of each clot using a semiautomated quantification program. Semiquantitative measures of clot burden were also computed. The resolution rates of the total clot volume, as well as clot volumes of the central (main and lobar) and peripheral vessels (segmental and subsegmental), were analyzed. RESULTS: The mean (± SD) clot volume per study was 3403.3 ± 6505.6 mm(3) at baseline and 531.6 ± 2383.5 mm(3) at the follow-up pulmonary CTA. Overall, 85 patients (77% ) showed complete resolution at the follow-up pulmonary CTA. Complete resolution was seen in 17 of 30 patients (56.7%) at a follow-up interval of 1-14 days, in 24 of 31 patients (77.4%) at 29-90 days, and in 32 of 34 patients (94.1%) after 90 days. The total clot volume measurements summed for all patients decreased by 78% (central clot, 69.4%; peripheral clot, 86.0%) at 14 days, by 96.6% (central clot, 93.4%; peripheral clot, 100%) at 90 days, and by 97.7% (central clot, 95.9%; peripheral clot, 100%) after 90 days. CONCLUSION: Clot burden resolved completely in 77% of patients during the follow-up period. Our analysis showed that clots resolved faster in the peripheral arteries than in the central pulmonary arteries.

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.

Predicting severe proximal left anterior descending coronary artery stenosis using proximal left anterior descending coronary artery tortuosity and the angle between the left main and anterior descending coronary arteries: a retrospective cross-sectional study.

Background: Coronary bifurcation angles influence plaque initiation in the coronary artery, and changes in blood flow caused by tortuosity in the coronary arteries can reduce blood pressure distal to the tortuous portion of the coronary artery, leading to myocardial ischemia. We aimed to describe two factors (coronary artery tortuosity and bifurcation angle) as one descriptor for the evaluation of proximal left anterior descending coronary artery (LAD) disease. Methods: We reviewed the medical records of 133 consecutive patients who underwent computed tomography angiography (CTA) for angina symptoms between November 2019 and January 2020. The patients were divided into two groups according to the presence of significant LAD stenosis on CTA (defined as LAD stenosis >50%). The straight length of the vessel was measured using the central luminal line of the flow path, and, calculated using proprietary algorithms in TeraRecon software. We used three-dimensional volume rendering and two-dimensional axial images to measure the left main coronary artery (LM)-LAD angles. Results: In the univariate analysis, there were significant differences in the linear distance between the endpoints of the 20 mm actual curve of the LAD (d20), cosine value for LM-LAD angle (cosθ) <0.8, age, presence of hypertension or diabetes, and number of pack years [hazard ratio (HR): 2.70, 8.04, 1.05, 3.70, 2.82, and 1.04; P=0.029, P<0.001, P=0.020, P=0.024, P=0.021, and P=0.002, respectively]. However, in the multivariate analysis, the cosθ multiplied by d20 (d20*cosθ) <15.5, presence of hypertension and number of pack years (HR: 11.36, 4.54, and 1.04; P<0.001, P=0.019, and P=0.003, respectively) were predictors of significant proximal LAD stenosis. Conclusions: As the tortuosity and LM-LAD angle increased (d20 and cosθ decreased, respectively), the chance of proximal LAD lesions formation increased. d20*cosθ might be useful as a predictor of proximal LAD stenosis.