Hyperdense artery sign on computed tomography in acute ischemic stroke

Despite the advent and growing availability of magnetic resonance imaging, the imaging modality of choice in the acute care of stroke patients in many institutions remains computed tomography. The hyperdense artery sign is the earliest marker of acute ischemic stroke. In this short review, we discuss the pathology, incidence, clinical aspects, imaging findings, significance and future questions that need to be addressed concerning this important sign.     

Pulmonary artery diameters measured by multidetector-row computed tomography in healthy adults

Background: The range of the diameters of pulmonary arteries (PA) is not fully shown in the current literature. Contrast-enhanced computed tomography (CT) of the thorax might be used for measuring diameters of the PA.

Purpose: To determine the diameters of PAs in subjects with normal PA pressure by using thoracic CT.

Material and Methods: 126 subjects aged between 19 and 46 years, having normal thoracic CTs (5-mm slice thickness) and normal PA pressures (≤25 mmHg, determined by echocardiography), were included in the study. The diameters of the main, right, and left PAs were measured by using multidetector CT.

Results: The main PA diameters of all the subjects showed a normal distribution, and the mean was 24.0±2.8 mm. The main PA diameters in male and female subjects also showed a normal distribution. The difference between the sexes for the main PA diameters was not significant (P = 0.08). There were correlations between main PA diameter and body-mass index (BMI) (R = 0.41, P = 0.001) and weight (R = 0.34, P = 0.001). However, there was no significant correlation between main PA diameter and height (R = 0.05, P = 0.6).

Conclusion: This study suggests that diameters of the main PA and its main branches show a normal distribution in subjects having normal PA pressures. Based on our findings, the upper limits of the main, right, and left PA diameters are 29.5 mm, 19.8 mm, and 22.1 mm, respectively, in healthy adults.     

Computed tomography of a traumatic hepatic arterial pseudoaneurysm

We report a case of trauma causing the formation of a pseudoaneurysm of the proper hepatic artery. The preoperative computed tomographic (CT) finding of decreased enhancement of the left lobe of the liver was suggestive of ischemia or infarct secondary to hepatic arterial injury. A proper hepatic artery pseudoaneurysm was discovered on a follow-up postoperative CT. Retrospective review of the preoperative CT revealed the presence of a focal hematoma and an indistinct proper hepatic arterial segment at the site of the pseudoaneurysm. Although the pseudoaneurysm was not discovered intraoperatively, it was later confirmed by angiography and duplex ultrasound. The patient demonstrated extensive necrosis in the left lobe of the liver on the follow-up CT. The nature of the liver perfusion abnormalities that led to these findings is discussed.     

Transcatheter coil embolization of a complex pulmonary artery pseudoaneurysm with thyrocervical trunk-pulmonary arterial fistulization in a patient with cystic fibrosis and massive hemoptysis

Pulmonary artery pseudoaneurysm (PAP) is a rare cause of life-threatening hemoptysis and tends to develop in the setting of infection, neoplasm, or trauma. Successful endovascular coil embolization has demonstrated effectiveness in treating PAPs and is now the treatment of choice for these patients. Vascular supply to PAPs is highly variable and often requires embolization of both the systemic and pulmonary feeding vessels. This is a case report of a successful transcatheter coil embolization of a complex PAP with a thyrocervical trunk-pulmonary arterial fistula in a patient with massive hemoptysis in the setting of advanced cystic fibrosis.     

The use of computed tomography in the diagnosis of coronary artery bypass graft patency

In a preliminary evaluation of the use of dynamic computed tomography (CT) for the detection of patent aortocoronary bypass grafts, 30 patients were scanned either during the early postoperative peroid or after graft patency was determined by angiography. To visualize the proximal grafts, CT scans were taken through the aortic root following an intravenous bolus injection of contrast medium. Patent bypass grafts to the left anterior descending and right coronary arteries were demonstrated in 77.5%, while posterior grafts to the circumflex and obtuse marginal coronary arteries were detected in 40%. With its pontential for extracting dynamic events, CT scanning provides a new, noninvasive modality for the diagnosis of patent bypass grafts, which heretofore have only been visualized by selective angiography.     

Middle mesenteric artery: Angiographic and three-dimensional computed tomography findings

The middle mesenteric artery, also known as the third mesenteric artery, is a very rare anomaly. Several anatomical variations of middle mesenteric artery have been reported; in these reports, the right colic artery and/or middle colic artery often originate directly from the aorta. Here, we report a middle mesenteric artery in which the middle colic artery originated directly from the abdominal aorta. We also provide three-dimensional computed tomography and angiography findings and discuss anatomical and embryological considerations.     

Triage of patients with suspected coronary artery disease using multislice computed tomography

RATIONALE AND OBJECTIVES: Several studies have shown that multislice computed tomography (MSCT) has a high sensitivity and specificity for detecting coronary artery stenoses. The aim of the present study was to investigate whether MSCT can reliably triage patients with suspected coronary artery disease (CAD) to coronary artery bypass grafting (CABG), percutaneous coronary intervention (PCI), or no revascularization. MATERIALS AND METHODS: A total of 123 patients with suspected CAD who were referred for conventional coronary angiography (CATH) additionally underwent MSCT (16*0.5 mm detector collimation). Therapeutic decisions made on the basis of CATH and MSCT strictly following current guidelines for treatment of CAD were compared with decisions made by a cardiac surgeon and an interventional cardiologist. Only MSCTs with at least adequate image quality in all coronary segments were included in the analysis (94/123). RESULTS: Decisions made on the basis of MSCT and CATH according to guidelines did not differ significantly (agreement of 88%, 82 of 94, P = .319). The therapeutic decisions made by the interventional cardiologist and the cardiac surgeon based on CATH differed significantly (overall agreement of 79%, 74 of 94 cases, P < .001; cardiologist: 78% PCI and 22% CABG versus surgeon: 38% PCI and 62% CABG), whereas there was 100% agreement regarding decisions for or against invasive treatment. CONCLUSIONS: MSCT shows good agreement with CATH in triaging patients with suspected CAD to CABG, PCI, or no revascularization. The choice of revascularization procedure is significantly more strongly influenced by whether an interventional cardiologist or a cardiac surgeon makes the decision than by the diagnostic test on which the decision is based.     

Carotid computed tomography angiography after cobalt-based alloy carotid artery stenting using ultra-high-resolution computed tomography with model-based iterative reconstruction

In conventional carotid computed tomographic angiography, the artifacts of the stent vary depending on the structure and characteristics of the alloy type. Cobalt-based alloy stents have been reported to exhibit high artifacts, and accurate evaluation of the internal lumen can be difficult. Recently, ultra-high-resolution computed tomography scanner systems have become available for clinical practice. The primary features of this computed tomography scanner are a 0.25-mm detector row width and a 1024 × 1024 matrix. We report a case-series of carotid artery stenting using a cobalt-based alloy stent scanned by an ultra-high-resolution computed tomography scanner system and model-based iterative reconstruction. We also report that the combination of the ultra-high-resolution computed tomography scanner system with model-based iterative reconstruction would be useful to evaluate vessel patency after placement of a cobalt-based alloy stent.     

Bleeding pulmonary artery pseudoaneurysm secondary to squamous cell lung cancer: computed tomography findings and endovascular management

A case of bleeding pulmonary artery pseudoaneurysm secondary to squamous cell lung cancer is reported. The patient presented with massive hemoptysis, diagnosis was made with multidetector computed tomography, and the pseudoaneurysm was successfully embolized with platinum coils. Hemoptysis ceased following the procedure.     

Renal artery mycotic pseudoaneurysm: diagnosis with multi-detector computed tomographic angiography

Renal artery mycotic pseudoaneurysms are uncommon complications of bacterial endocarditis and bacteremia. Complications include hemorrhage and refractory bacteremia, and prompt diagnosis can lead to appropriate treatment. Reported is a case where multi-detector computed tomography angiography led to the correct diagnosis.     

Multi-detector computed tomography of acute abdomen

Acute abdominal pain is one of the most common causes for referrals to the emergency department. The sudden onset of severe abdominal pain characterising the acute abdomen requires rapid and accurate identification of a potentially life-threatening abdominal pathology to provide a timely referral to the appropriate physician. While the physical examination and laboratory investigations are often non-specific, computed tomography (CT) has evolved as the first-line imaging modality in patients with an acute abdomen. Because the new multi-detector CT (MDCT) scanner generations provide increased speed, greater volume coverage and thinner slices, the acceptance of CT for abdominal imaging has increased rapidly. The goal of this article is to discuss the role of MDCT in the diagnostic work-up of acute abdominal pain.     

Postoperative inverted intercostal hernia incidentally detected by chest computed tomography in a patient with COVID-19

Inverted intercostal hernias are uncommon, and even more so when comprised of soft tissue instead of lung parenchyma in the postoperative context. This report demonstrates a case in with such a hernia was diagnosed through chest multidetector computerized tomography in a 48-year-old woman who presented to the emergency room with respiratory symptoms and tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). She had positive surgical history for left lower lobectomy with bronchoplastic procedure and mediastinal lymphadenectomy, due to an endobronchial typical carcinoid tumor a few years ago. Therefore, it is important for radiologists to be aware of the imaging characteristics of inverted intercostal hernias, to avoid diagnostic errors.     

Primary heart angiosarcoma detected by computed tomography and magnetic resonance imaging

We report a case of primary heart angiosarcoma and its appearance on plain and post-contrast computed tomography and magnetic resonance imaging in 21-year-old woman. The tumour involved the right atrium, expanded superiorly among the superior vena cava, ascending aorta and innominate vein, and infiltrated the pericardium. The tumour was disseminated into lungs, liver and bones at the time of its clinical presentation. Received 24 January 1997; Revision received 13 March 1997; Accepted 28 April 1997     

Multi-detector computed tomography angiography of the hepatic artery in liver transplant recipients

Purpose: To evaluate the ability of multi-detector row computed tomography angiography (CTA) in detecting hepatic artery complications in the follow-up of liver transplant patients, performing volume-rendering as reconstruction technique.

Material and Methods: The anatomy of hepatic artery was studied in 27 liver transplant recipients with a four-row CT scanner using the following parameters: collimation, 1 mm; slice width, 1 mm; table feed, 6-8 mm/s; spiral reconstruction time, 0.5 s; reconstruction interval, 0.5 mm; mAs, 160; kVp, 120. Before the study, the patients received 1000 ml of water as oral contrast agent to produce negative contrast in the stomach and the small bowel. A non-ionic contrast medium was infused intravenously at a rate of 5 ml/s with a bolus tracking system. Volume-rendering of hepatic artery was performed with the 3D Virtuoso software.

Results: The celiac trunk, the hepatic artery, and the right and left hepatic arteries were successfully displayed in high detail in all patients. Side branches, including small collaterals, and hepatic artery anastomosis could also be readily visualized. Volume-rendered CTA detected six hepatic artery stenoses, two hepatic artery thromboses, and two intrahepatic pseudoaneurysms. In two cases, CT detected hepatic artery stenosis with a diameter reduction of less than 50%, while digital subtraction angiography showed a normal artery.

Conclusion: Volume-rendered multi-detector CTA is a promising non-invasive technique, since it allows images of high quality to be generated with excellent anatomical visualization of the hepatic artery and its complications in liver transplant recipients.     

Variability of repeated coronary artery calcium scoring and radiation Dose on 64- and 16-slice computed tomography by prospective electrocardiographically-triggered axial and retrospective electrocardiographically-gated spiral computed tomography: a phantom study

RATIONALE AND OBJECTIVES: We sought to compare coronary artery calcium (CAC) scores, the variability and radiation doses on 64- and 16-slice computed tomography (CT) scanners by both prospective electrocardiographically (ECG)-triggered and retrospective ECG-gated scans. MATERIALS AND METHODS: Coronary artery models (n = 3) with different plaque CT densities (approximately 240 Hounsfield units [HU], approximately 600 HU, and approximately 1000 HU) of four sizes (1, 3, 5, and 10 mm in length) on a cardiac phantom were scanned three times in five heart rate sequences. The tube current-time products were set to almost the same on all four protocols (32.7 mAs for 64-slice prospective and retrospective scans, 33.3 mAs for 16-slice prospective and retrospective scans). Slice thickness was set to 2.5 mm to keep the radiation dose low. Overlapping reconstruction with a 1.25-mm increment was applied on the retrospective ECG-gated scan. RESULTS: The CAC scores were not different between the four protocols (one-factor analysis of variance: Agatston, P = .32; volume, P = .19; and mass, P = .09). Two-factor factorial analysis of variance test revealed that the interscan variability was different between protocols (P < .01) and scoring algorithms (P < .01). The average variability of Agatston/volume/mass scoring and effective doses were as follows: 64-slice prospective scan: 16%/15%/11% and 0.5 mSv; 64-slice retrospective scan: 11%/11%/8% and 3.7 mSv; 16-slice prospective scan: 20%/18%/13% and 0.6 mSv; and 16-slice retrospective scan: 16%/15%/11% and 2.9 to 3.5 mSv (depending on the pitch). CONCLUSION: Retrospective ECG-gated 64-slice CT showed the lowest variability. Prospective ECG-triggered 64-slice CT, with low radiation dose, shows low variability on CAC scoring comparable to retrospective ECG-gated 16-slice CT.