Seung Min Yoo

MDCT Evaluation of Acute Aortic Syndrome

This article provides a summary of acute aortic syndrome (AAS), focusing especially on the multidetector CT technique and findings of AAS, as well as recent concepts regarding the subtypes of AAS, consisting of aortic dissection, intramural hematoma, penetrating atherosclerotic ulcer, and unstable aortic aneurysm.

Rarity of isolated pulmonary embolism and acute aortic syndrome occurring outside of the field of view of dedicated coronary CT angiography

Background Although triple rule-out CT angiography (TRO) to simultaneously evaluate acute coronary syndrome (ACS), pulmonary embolism (PE), and acute aortic syndrome (AAS) is increasingly used in many institutions, TRO is inevitably associated with increased radiation exposure due to extended z-axis coverage compared with dedicated coronary CT angiography (DCTA). Purpose To determine the frequency of exclusion of findings of AAS, PE, and significant incidental non-cardiac pathology that may be the cause of acute chest pain when using a restricted DCTA field of view (FOV). Material and Methods We retrospectively reviewed CT images and charts of 103 patients with acute PE and 50 patients with AAS. Either non-ECG gated dedicated pulmonary or aortic CT angiography was performed using 16- or 64-slice multidetector CT (MDCT). We analyzed the incidence of isolated PE, AAS, or significant non-cardiac pathology outside of DCTA FOV (i.e. from tracheal carina to the base of heart). Results There were two cases of isolated PE (2/103, 1.9%) excluded from the FOV of DCTA. One case of PE was isolated to the subsegmental pulmonary artery in the posterior segment of the right upper lobe. In the second case, pulmonary embolism in the left main pulmonary artery was located out of the FOV of DCTA because the left main pulmonary artery was retracted upwardly by fibrotic scar in the left upper lobe due to prior tuberculosis. There was no case of AAS and significant non-cardiac pathology excluded from the FOV of DCTA. AAS (n = 50) consisted of penetrating atherosclerotic ulcer (n = 7), intramural hematoma (n = 5) and aortic dissection (n = 38). Conclusion As isolated PE, AAS, and significant non-cardiac pathology outside of the DCTA FOV rarely occur, DCTA may replace TRO in the evaluation of patients with non-specific acute chest pain and a low pre-test probability of PE or aortic dissection.

Current Concepts in Cardiac CT Angiography for Patients With Acute Chest Pain

This article presents specific examples of delayed diagnosis of acute coronary syndrome, acute aortic dissection, and pulmonary embolism resulting from evaluating patients with nonspecific acute chest pain who did not undergo immediate dedicated coronary CT angiography (CTA) or triple rule-out protocol (TRO). These concrete examples of delayed diagnosis may advance the concept of using cardiac CTA (i.e., dedicated coronary CTA versus TRO) to triage patients with nonspecific acute chest pain. This article also provides an overall understanding of how to choose the most appropriate examination based on the specific clinical situation in the emergency department (i.e., dedicated coronary CTA versus TRO versus dedicated pulmonary or aortic CTA), how to interpret the CTA results, and the pros and cons of biphasic versus triphasic administration of intravenous contrast material during TRO examination. A precise understanding of various cardiac CTA protocols will improve the diagnostic performance of radiologists while minimizing hazards related to radiation exposure and contrast use.

Lithiasis in a heterotopic pancreas of the stomach

A heterotopic pancreas is a relatively uncommon abnormality and usually of no clinical importance. A heterotopic pancreas is subject to various pathologic changes occurring in the pancreas, however, such as acute pancreatitis, cyst or abscess formation, pancreatic cancer, and islet cell tumor. We describe a rare case of a heterotopic pancreas presenting as a gastric submucosal mass with punctate calcifications occurring in a 43-year-old man.

Can the extent of epicardial adipose tissue thickness or the presence of descending thoracic aortic calcification predict significant coronary artery stenosis in patients with a zero coronary calcium score on multi-detector CT?

OBJECTIVE The purpose of this study was to evaluate whether the extent of epicardial adipose tissue (EAT) thickness or the presence of descending thoracic aortic calcification on multi-detector CT (MDCT) can predict the presence of significant coronary artery stenosis in patients with negative coronary artery calcium (CAC). METHODS We enrolled 90 patients with negative CAC in whom both coronary CT angiography (CTA) and conventional angiography had been performed. Group 1 consisted of patients (n=27) with significant coronary artery stenosis (≥50%), whereas group 2 (n=63) had non-obstructive coronary artery stenosis (<50%) on conventional angiography. We analyzed whether or not there is a significant difference in EAT thickness or the incidence of calcification of descending thoracic aorta among the two groups. RESULTS There was no significant difference between EAT thickness on MDCT among the two groups. There was also no significant difference in the incidence of descending thoracic aortic calcification between group 1 (7/27, 25.9%) and group 2 (14/63, 22.2%) (p>0.05). CONCLUSIONS Neither the presence of abundant EAT nor calcification of descending thoracic aorta is a marker of significant coronary artery stenosis in patients with negative CAC.

MDCT evaluation of atherosclerotic coronary artery disease: What should radiologists know?

As an important tool for diagnosing acute coronary syndrome and stable angina, coronary CT angiography has been increasingly being performed in patients presenting with atypical chest pain. In order to help treating patients more efficiently, it is crucial for radiologists to have a comprehensive understanding about mechanisms and clinical aspects as well as CT findings of coronary atherosclerosis per se. A thorough understanding and optimal performance of coronary CT angiography may lead to reduction of unjustified downstream testing. This article provides a clinical and radiological overview of coronary atherosclerosis, and a practical guideline about how to interpret degree of stenosis on coronary CT angiography.

Association of insulin resistance and coronary artery remodeling: an intravascular ultrasound study

BackgroundThere are few studies that investigated the correlation between insulin resistance (IR) and the coronary artery remodeling. The aim of the study is to investigate the association of IR measured by homeostasis model assessment of insulin resistance (HOMA-IR) and coronary artery remodeling evaluated by intravascular ultrasound (IVUS).MethodsA total of 298 consecutive patients who received percutaneous coronary interventions under IVUS guidance were retrospectively enrolled. The value of HOMA-IR more than 2.5 was considered as IR positive. Metabolic syndrome was classified according to NCEP ATP III guidelines. The remodeling index was defined as the ratio of the external elastic membrane (EEM) area at the lesion site to the EEM area at the proximal reference site.ResultsA total of 369 lesions were analyzed (161 lesions in HOMA-IR positive and 208 lesions in HOMA-IR negative). Remodeling index was significantly higher in the HOMA-IR positive group compared with the negative group (HOMA-IR positive vs. negative: 1.074 ± 0.109 vs. 1.042 ± 0.131, p = 0.013). There was a significant positive correlation between remodeling index and HOMA-IR (p = 0.010). Analysis of HOMA-IR according to remodeling groups showed increasing tendency of HOMA-IR, and it was statistically significant (p = 0.045). Multivariate analysis revealed that only HOMA-IR was an independent predictor of remodeling index (r = 0.166, p = 0.018).ConclusionIncreased IR estimated by HOMA-IR was significantly associated with a higher remodeling index and positive coronary artery remodeling.

The Ratio of Descending Aortic Enhancement to Main Pulmonary Artery Enhancement Measured on Pulmonary CT Angiography as a Finding to Predict Poor Outcome in Patients with Massive or Submassive Pulmonary Embolism

Background The purpose of this study was to evaluate whether measuring the ratio of descending aortic enhancement (DAE) to main pulmonary artery enhancement (MPAE) on pulmonary computed tomography angiography (PCTA) can predict poor outcome in patients with acute massive or submassive pulmonary embolism (PE). Methods We retrospectively, reviewed computed tomgraphy findings and charts of 37 patients with acute PE and right ventricular dysfunction. We divided the enrolled patients into 3 groups; group Ia (n=8), comprised of patients with major adverse event (MAE); group Ib (n=5), consisted of those with PE-related MAE; and group II (n=29), those without MAE. We analyzed the right ventricular diameter (RVD)/left ventricular diameter (LVD) and DAE/MPAE on PCTA. Results For observer 1, RVD/LVD in group Ia (1.9±0.36 vs. 1.44±0.38, p=0.009) and group Ib (1.87±0.37 vs. 1.44±0.38, p=0.044) were significantly higher than that of group II. For observer 2, RVD/LVD in group Ia (1.71±0.18 vs. 1.41±0.47, p=0.027) was significantly greater than that of group II, but RVD/LVD of group Ib was not (1.68±0.2 vs. 1.41±0.47, p=0.093). For both observers, there was a significant difference of DAE/MPAE between group Ib and group II (0.32±0.15 vs. 0.64±0.24, p=0.005; 0.34±0.16 vs. 0.64±0.22, p=0.004), but no significant difference of DAE/MPAE between group Ia and group II (0.51±0.3 vs. 0.64±0.24, p=0.268; 0.53±0.29 vs. 0.64±0.22, p=0.302). Intra-class correlation coefficient (ICC) for the measurement of DAE/MPAE (ICC=0.97) was higher than that of RVD/LVD (ICC=0.74). Conclusion DAE/MPAE measured on PCTA may predict PE-related poor outcomes in patients with massive or submassive PE with an excellent inter-observer agreement.

A Case of Complete Unroofed Coronary Sinus Syndrome Combined With Coronary Sinus Stenosis Leading to Asymptomatic Presentation

We describe a patient with an asymptomatic complete unroofed coronary sinus (CS) syndrome associated with the CS stenosis in the absence of a persistent left superior vena cava (SVC) as identified on coronary computed tomography angiography. There was a large defect between the CS and the left atrium (i.e. a large left-to-right shunt), but an unusual combination of the absence of a persistent left SVC (i.e. no risk for brain abscess due to the absence of a right-to-left shunt) and the CS stenosis (i.e. a markedly reduced degree of a left-to-right shunt), resulting in an asymptomatic presentation.

Traumatic aortic regurgitation combined with descending aortic pseudo-aneurysm secondary to blunt chest trauma : online article - case report

Rupture of the aorta is a relatively rare complication of blunt chest trauma, and traumatic rupture of the aortic valve is even rarer. Even though both result from blunt chest trauma, the causative mechanisms of aortic valve injury differ from those of descending aortic rupture. There are no previous reports in the literature of simultaneous injuries to both the descending aorta and the aortic valve. We report a case of a 70-year-old man who presented with traumatic aortic regurgitation combined with traumatic pseudoaneurysm of the aortic isthmus following blunt chest trauma, and its successful repair with a hybrid surgical strategy.