Diagnostic pitfalls in computed tomography of the chest.

Anatomical variants and imaging artifacts on thoracic computed tomography (CT), when unrecognized as such, can lead to radiological misinterpretation and erroneous diagnosis. This is a concise review of 15 common CT diagnostic pitfalls due to anatomical variants and imaging artifacts which have potential to be misinterpreted as significant pathology, such as neoplasia, infection, traumatic injury, interstitial lung disease, pleural disease, or vascular lesions.

Imaging-Based Surrogate Markers of Epidermal Growth Factor Receptor Mutation in Lung Adenocarcinoma: A Local Perspective.

PURPOSE: To identify computed tomography (CT) features of epidermal growth factor receptor (EGFR) mutation-positive lung adenocarcinoma in Canadian population and whether imaging-based surrogate markers of EGFR mutation in our population were similar to those found in the Asian population. MATERIALS AND METHODS: Pretreatment CT scans of 223 patients with adenocarcinoma of the lung (112 with EGFR mutation and 111 without mutation) were retrospectively assessed for 20 specific CT features by 2 radiologists, who were blinded to the status of EGFR mutation. Univariate and multivariate logistic regression analyses as well as areas under the receiver operating characteristic curve were performed to discriminate characteristics of EGFR-activating mutation features. RESULTS: Epidermal growth factor receptor mutation-positive adenocarcinomas were more frequently found in female (P < .03), less than 20 pack-year smoking history (P < .001), smaller tumor (P < .01), spiculated margins (P < .05), without centrilobular emphysema (P < .001), and without lymphadenopathy (P < .05), similarly to the Asian population. Multivariate logistic regression analyses of combined clinical and radiological features identified less than 20 pack-year smoking history, smaller tumor diameter, fine or coarse spiculations, noncentral location of the tumor, and lack of centrilobular emphysema and pleural attachment as the strongest independent prognostic factors for the presence of an EGFR mutation. These combined features improved prognostic ability area under the curve to 0.879, compared to 0.788 for clinical features only. CONCLUSION: Several CT findings may help predict the presence of an activating mutation in EGFR in lung adenocarcinomas in our Canadian population. Combining clinical and radiological features improves prognostic ability to determine the EGFR mutation status compared to clinical features alone.

Many Faces of Thoracic Histoplasmosis-Pictorial Essay.

Histoplasmosis is primarily a pulmonary fungal infection with a vast array of radiological manifestations, which can mimic a number of thoracic diseases. This article reviews various presentations of histoplasmosis on chest imaging.

Imaging of Post Transthoracic Needle Biopsy Complications.

When faced with characterization of a suspicious lung lesion, transthoracic needle biopsy (TTNB) is the standard technique used to retrieve a pathological specimen. Usual complications reported for this intervention are pneumothorax, hemorrhage, air embolism, and tumor seeding. This pictorial essay illustrates imaging of these complications.

Laparoscopic Sleeve Gastrectomy: A Radiological Guide to Common Postsurgical Failure.

Laparoscopic sleeve gastrectomy is one of the most common bariatric procedures worldwide. It has recently gained in popularity because of a low complication rate, satisfactory resolution of comorbidities, and excellent weight loss outcome. This article reviews the surgical technique, expected postsurgical imaging appearance, and imaging findings of common complications after laparoscopic sleeve gastrectomy. Understanding of the surgical technique of laparoscopic sleeve gastrectomy and of the normal postsurgical anatomy allows accurate interpretation of imaging findings in cases of insufficient weight loss, weight regain, and postsurgical complications.

A New Method to Evaluate Atrial Hemodynamic and Quantify Mitral Regurgitation using Cardiovascular Magnetic Resonance: The Pulmonary Venous Flow Approach.

Pulmonary venous flow (PVF) provides incremental information on left ventricular (LV) diastolic function, and can support the diagnosis of severe mitral regurgitation (MR). The suggestion has been made to combine the left atrial filling volume (LA Fill) and PVF for estimating the mitral regurgitant volume, but echocardiographic PVF evaluation is known to have many limitations. The present case report includes an example of how to assess PVF using cardiovascular magnetic resonance, and a new method is proposed for quantification of the mitral regurgitant volume.

Volumetric Single-Beat Coronary Computed Tomography Angiography: Relationship of Image Quality, Heart Rate, and Body Mass Index. Initial Patient Experience With a New Computed Tomography Scanner.

BACKGROUND: Cardiac computed tomography (CT) image quality (IQ) is very important for accurate diagnosis. We propose to evaluate IQ expressed as Likert scale, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) from coronary CT angiography images acquired with a new volumetric single-beat CT scanner on consecutive patients and assess the IQ dependence on heart rate (HR) and body mass index (BMI). METHODS: We retrospectively analyzed the data of the first 439 consecutive patients (mean age, 55.13 [SD, 12.1] years; 51.47% male), who underwent noninvasive coronary CT angiography in a new single-beat volumetric CT scanner (Revolution CT) to evaluate chest pain at West Kendall Baptist Hospital. Based on patient BMI (mean, 29.43 [SD, 5.81] kg/m), the kVp (kilovolt potential) value and tube current were adjusted within a range of 80 to 140 kVp and 122 to 720 mA, respectively. Each scan was performed in a single-beat acquisition within 1 cardiac cycle, regardless of the HR. Motion correction software (SnapShot Freeze) was used for correcting motion artifacts in patients with higher HRs. Autogating was used to automatically acquire systolic and diastolic phases for higher HRs with electrocardiographic milliampere dose modulation. Image quality was assessed qualitatively by Likert scale and quantitatively by SNR and CNR for the 4 major vessels right coronary, left main, left anterior descending, and left circumflex arteries on axial and multiplanar reformatted images. Values for Likert scale were as follows: 1, nondiagnostic; 2, poor; 3, good; 4, very good; and 5, excellent. Signal-to-noise ratio and CNR were calculated from the average 2 CT attenuation values within regions of interest placed in the proximal left main and proximal right coronary artery. For contrast comparison, a region of interest was selected from left ventricular wall at midcavity level using a dedicated workstation. We divided patients in 2 groups related to the HR: less than or equal to 70 beats/min (bpm) and greater than 70 bpm and also analyzed them in 2 BMI groupings: BMI less than or equal to 30 kg/m and BMI greater than 30 kg/m. RESULTS: Mean SNR was 8.7 (SD, 3.1) (n = 349) for group with HR 70 bpm or less and 7.7 (SD, 2.4) (n = 78) for group with HR greater than 70 bpm (P = 0.008). Mean CNR was 6.9 (SD, 2.7) (n = 349) for group with HR 70 bpm or less and 5.9 (SD, 2.2) (n = 78) for group with HR 70 bpm or greater (P = 0.002). Mean SNR was 8.8 (SD, 3.2) (n = 249) for group with BMI 30 kg/m or less and 8.1 (SD, 2.6) (n = 176) for group with BMI greater than 30 kg/m (P = 0.008). Mean CNR was 7.0 (SD, 2.8) (n = 249) for group with BMI 30 kg/m or less and 6.4 (SD, 2.4) (n = 176) for group with BMI greater than 30 kg/m (P = 0.002). The results for mean Likert scale values were statistically different, reflecting difference in IQ between people with HR 70 bpm or less and greater than 70 bpm, BMI 30 kg/m or less, and BMI greater than 30 kg/m.

Multimodality imaging of a rare intracardiac bronchogenic cyst.

The authors report a case of pathologically proven intracardiac bronchogenic cyst embedded within the interatrial septum of a 30-year-old woman presenting with chest pain and first-degree AV block. Multimodality imaging played an essential role in the discovery, investigation, and diagnosis of this extremely rare entity.

A fatal complication of ultrasound-guided abdominal paracentesis.

Ultrasound-guided abdominal paracentesis is a procedure that is frequently performed by radiologists for both diagnostic and therapeutic purposes. This procedure has been shown to be safe with few complications. We report the case of a patient who underwent an ultrasound-guided therapeutic abdominal paracentesis for refractory ascites complicated by intraperitoneal hemorrhage leading to death. This case suggests that ultrasound-guided paracentesis may need to become a more standardized procedure and that in the event of hemorrhage, alternative treatment options such as embolization or surgical intervention should be utilized when manual compression fails.

Cor triatriatum simulating a left atrial mass in adult patient.

We report a case of non-thrombosed cor triatriatum sinister simulating a cardiac mass on thoracic CT angiogram in a 58-year-old man presenting with acute chest pain. Following additional imaging with cardiac CT and MRI, and otherwise unremarkable cardio-pulmonary work-up, diagnosis of presumably coincidental cor triatriatum was established.

Rare case of bilateral bronchopulmonary sequestration.

Pulmonary sequestration is a rare congenital bronchopulmonary malformation with an estimated incidence of less than 6%. It is described as the abnormal formation of nonfunctional lung tissue that receives its blood supply from systemic circulation rather than the bronchial tree. Most are unilateral, while a miniscule proportion is bilateral. Delayed diagnosis can result in recurrent pneumonia, failure to thrive, regular hospital visits, morbidity and even fatality. Thus, it is important to raise awareness of this condition. Herein, we present a case of a 42-year-old patient with bilateral pulmonary sequestration (BPS) on a triple rule out CT angiography (TRO-CTA).

Angiomatoid fibrous histiocytoma: magnetic resonance imaging appearance in 2 cases.

OBJECTIVE: Angiomatoid fibrous histiocytoma (AFH) is a rare soft tissue tumor usually affecting the extremities of children and young adults and has a favorable prognosis. The purpose of this study was to report the magnetic resonance imaging appearance in 2 cases of AFH. CONCLUSIONS: Although the overall features of AFH can be confused with other subtypes of malignant fibrous histiocytoma, the young age at presentation, the location of the mass, the presence of intralesional blood-filled cystic spaces with fluid-fluid levels, associated features of hemosiderin deposition, and an enhancing fibrous pseudocapsule are all potential hints favoring this entity.

Cause determination of missed lung nodules and impact of reader training and education: Simulation study with nodule insertion software.

BACKGROUND: There are "blind spots" on chest computed tomography (CT) where pulmonary nodules can easily be overlooked. The number of missed pulmonary nodules can be minimized by instituting a training program with particular focus on the depiction of nodules at blind spots. PURPOSE: The purpose of this study was to assess the variation in lung nodule detection in chest CT based on location, attenuation characteristics, and reader experience. MATERIALS AND METHODS: We selected 18 noncalcified lung nodules (6-8 mm) suspicious of primary and metastatic lung cancer with solid (n = 7), pure ground-glass (6), and part-solid ground-glass (5) attenuation from 12 chest CT scans. These nodules were randomly inserted in chest CT of 34 patients in lung hila, 1st costochondral junction, branching vessels, paramediastinal lungs, lung apices, juxta-diaphragm, and middle and outer thirds of the lungs. Two residents and two chest imaging clinical fellows evaluated the CT images twice, over a 4-month interval. Before the second reading session, the readers were trained and made aware of the potential blind spots. Chi-square test was used to assess statistical significance. RESULTS: Pretraining session: Fellows detected significantly more part-solid ground-glass nodules compared to residents (P = 0.008). A substantial number of nodules adjacent to branching vessels and posterior mediastinum were missed. Posttraining session: There was a significant increase in detectability independent of attenuation and location of nodules for all readers (P < 0.0008). CONCLUSION: Dedicated chest CT training improves detection of lung nodules, especially the part-solid ground-glass nodules. Detection of nodules adjacent to branching vessels and the posterior mediastinal lungs is difficult even for fellowship-trained radiologists.

Hemiazygous-accessory hemiazygous continuation of double inferior vena cava.

We report a case of hemiazygous-accessory hemiazygous continuation of a double IVC with absent azygous vein, incidentally discovered in an adult patient.

Anomalous right vertebral artery arising from the arch of aorta: report of three cases.

The right vertebral artery most commonly originates as the first branch of the right subclavian artery. Although anatomical variants of the aortic arch are commonly encountered on cross-sectional imaging, certain variants of the right vertebral artery are exceedingly rare. In this report, we present 3 cases of aberrant right vertebral artery arising as the last branch of the aortic arch, a very rare variant.

Use of cardiovascular magnetic resonance in the evaluation of a giant right atrial appendage aneurysm: a case report and review of the literature.

BACKGROUND: Right atrial appendage aneurysms are rare entities that may have significant clinical consequences. When co-existing with atrial fibrillation, patients are at risk of developing pulmonary or paradoxical systemic emboli. CASE PRESENTATION: An elderly patient presented to medical attention with symptoms of acute diverticulitis. On abdominal computed tomography, a massively enlarged right atrial appendage aneurysm was discovered incidentally. The aneurysm caused marked compression of the right ventricle and contained an area of hypoenhancement concerning for an intraluminal thrombus. Gadolinium-enhanced cardiovascular magnetic resonance was performed and first-pass perfusion images demonstrated that the area of hypoenhancement was in fact poorly mixing blood. The patient was therefore managed medically. CONCLUSION: Right atrial appendage aneurysms are infrequently encountered cardiac abnormalities. In the literature, surgery has been offered to patients who are young, symptomatic, or have evidence of thrombotic disease, although whether this practice pattern is associated with superior clinical outcomes is unclear. In the present case, gadolinium-enhanced cardiovascular magnetic resonance imaging was used to exclude the presence of intraluminal thrombus in an elderly patient, which helped orient the patient's treating team towards medical-rather than surgical-therapy.

Aortic Calcification Progression in Heterozygote Familial Hypercholesterolemia.

BACKGROUND: Patients with homozygous and heterozygous familial hypercholesterolemia (HeFH) develop severe aortic calcifications in an age- and gene dosage-dependent manner. The purpose of this study was to determine the rate of progression of aortic calcification in patients with HeFH. METHODS: We performed thoracoabdominal computed tomography scans and quantified aortic calcium (AoCa) score in 16 HeFH patients, all with the null low-density lipoprotein (LDL) receptor DEL15Kb mutation. Patients (12 men, 4 women) were rescanned an average of 8.2 ± 0.8 years after the first scan. RESULTS: Mean LDL cholesterol (LDL-C) during treatment was 2.53 mmol/L; all patients were receiving high-dose statin/ezetimibe; 5 of 16 were receiving evolocumab. Baseline LDL-C was 7.6 ± 1.3 mmol/L. Aortic calcifications increased in all patients in an exponential fashion with respect to age. Age was the strongest correlate of AoCa score. Cholesterol, LDL-C, or age × cholesterol did not correlate with AoCa score or its progression. Control patients (n = 31; 8 male, 23 female; mean age 61 ± 11 years) who underwent virtual colonoscopy were rescanned over the same period and showed an abdominal AoCa score of 1472 ± 2489 compared with 7916 ± 7060 Agatston U (P < 0.001) in patients with HeFH during treatment (mean age, 60 ± 14 years). The rate of progression was 159 vs 312 Agatston U/y in control participants vs those with HeFH. CONCLUSIONS: HeFH patients exhibit accelerated aortic calcification that increases exponentially with age. LDL-C at baseline or during treatment seems to have little effect on the rate of progression of AoCa score. Strategies to prevent aortic calcifications with statins have not met with clinical success and novel approaches are required; statins might also contribute to the process of arterial calcification.

Multimodality imaging of a cardiac paraganglioma.

Paragangliomas are rare neuroendocrine tumors arising from the ganglia of the sympathetic or parasympathetic nervous system. Less than 160 cases of intrapericardial or intracardiac paragangliomas have been reported in the English language peer-reviewed medical literature. Here, we report a case of intrapericardial paraganglioma, which illustrates some typical multimodality imaging features of this rare entity.

Pattern of Failure Analysis in Metastatic EGFR-Mutant Lung Cancer Treated with Tyrosine Kinase Inhibitors to Identify Candidates for Consolidation Stereotactic Body Radiation Therapy.

INTRODUCTION: The role of stereotactic body radiation therapy (SBRT) in patients with metastatic lung cancer harboring epidermal growth factor receptor (EGFR) mutations is not defined. We evaluated the pattern of failure in patients receiving tyrosine kinase inhibitor (TKI) therapy to identify candidates for consolidation SBRT. METHODS: Computed tomography scans were reviewed in a cohort of EGFR-mutant patients enrolled on prospective TKI trials. Initial progression in sites of original disease (primary/metastatic) or new sites was classified as original site failure (OF) or distant site failure (DF), respectively. Simultaneous OF/DF was labeled ODF. Disease characteristics were analyzed for associations with patterns of failure using actuarial competing risks methodology. RESULTS: Complete serial imaging was available in 49 patients with measurable disease. Median time to any progression was 8.3 months. The majority failed initially in original disease sites with OF, ODF, and DF frequencies being 47.0%, 32.6%, and 20.4%, respectively. Primary tumor size was the most significant predictor of OF in univariate and multivariate analysis (p = 0.004). Median time to progression was 3 months shorter in patients with OF compared with DF. Ten patients (20%) were retroactively classified as consolidation SBRT candidates based on the extent of disease at time of best response to TKI therapy, and in seven of these, initial progression occurred in original tumor sites. CONCLUSION: Initial progression of TKI-treated cancers occurred predominantly in original disease sites. Consolidation SBRT was judged feasible in a subset of patients following maximum TKI response and may have prevented oligoprogression in most of these. In addition, we hypothesize that consolidation SBRT for residual disease could delay subsequent metastatic reseeding.