Hamid Mojibian

Impact of Adaptive Statistical Iterative Reconstruction (ASIR) on Radiation Dose and Image Quality in Aortic Dissection Studies: A Qualitative and Quantitative Analysis

OBJECTIVE The purpose of the study was to quantify the radiation dose reduction achieved when imaging the aorta using Adaptive Statistical Iterative Reconstruction (ASIR) and to determine if this has an effect on image quality. MATERIALS AND METHODS We retrospectively reviewed 31 CT angiography examinations of the thoracic and abdominal aorta performed with ASIR and 32 consecutive similar examinations performed without ASIR. Volume CT dose index (CTDI(vol)), dose-length product (DLP), aortic enhancement at multiple levels, aorta-to-muscle contrast-to-noise ratio at multiple levels, and subjective image quality were compared between the two groups. RESULTS The mean CTDI(vol) and DLP were significantly lower for the studies performed with ASIR versus studies without ASIR (15.6 vs 21.5 mGy, with an average difference of 5.8 mGy [95% CI 2.3-9.4 mGy] and 818 vs 1075 mGy × cm with an average difference of -257 mGy × cm [54-460 mGy × cm], respectively). Aortic enhancement, aortic signal-to-noise ratio, and aortic to muscle contrast-to-noise ratio were not different between the two groups. Subjectively, one reviewer preferred the non-ASIR images and one found the images equivalent. Both reviewers believed the images were of diagnostic quality. CONCLUSION A 29% decrease in CTDI(vol) and a 20% decrease in DLP were obtained in scans with ASIR compared with scans without ASIR, without a quantitative loss of image quality.

‘Bovine’ Aortic Arch – A Marker for Thoracic Aortic Disease

Objectives: Very few studies have addressed the clinical significance of ‘bovine’ aortic arch (BA). We sought to determine whether BA is associated with thoracic aortic disease, including thoracic aortic aneurysm, aortic dissection, aortic rupture, and accelerated aortic growth rate. Methods: We retrospectively reviewed CT and/or MRI scans of 612 patients with thoracic aortic disease and 844 patients without thoracic aortic disease to determine BA prevalence. In patients with thoracic aortic disease, we reviewed hospital records to determine growth rate, prevalence of dissection and rupture, and accuracy of radiology reports in citing BA. Results: 26.3% of the patients with thoracic aortic disease had concomitant BA, compared to 16.4% of the patients without thoracic aortic disease (p < 0.001). There was no association between BA and prevalence of dissection or rupture (p = 0.38 and p = 0.56, respectively). The aortic expansion rate was 0.29 cm/year in the BA group and 0.09 cm/year in the non-BA group (p = 0.004). Radiology reports cited BA in only 16.1% of the affected patients. Conclusions: (1) BA is significantly more common in patients with thoracic aortic disease than in the general population. (2) Aortas expand more rapidly in the setting of BA. (3) Radiology reports often overlook BA. (4) BA should not be considered a ‘normal’ anatomic variant.

Reverse Takotsubo Cardiomyopathy Associated With the Consumption of an Energy Drink

A 24-year-old man presented to the emergency room with chest pain, acute respiratory failure, and palpitations shortly after the ingestion of small amounts of an energy drink in little cups one after another. He was afebrile, with frequent runs of supraventricular and ventricular tachycardia and underlying sinus tachycardia. The patient was treated with fluids and metoprolol but required intubation because of progressive hypoxia. Chest x-ray revealed bilateral fluffy pulmonary infiltrates. His ECG was free of ischemic changes, and an echocardiogram at that time showed hypokinesis of all basal left ventricular segments with apical sparing and an ejection fraction of 35% (Figure 1 and Movie I in the online-only Data Supplement). His troponin was mildly increased and serially measured brain natriuretic peptide was elevated at 8000 pg/mL. Figure 1. ECG recorded at admission showing sinus tachycardia and nonspecific T-wave inversion in leads I and aVL. After treatment with furosemide, nitroglycerine, heparin, and aspirin, the patient responded with clinical improvement of vital signs and chest x-ray. Episodes of agitation and delirium ensued, delaying extubation. Computerized tomography brain scan and electroencephalogram were negative, and toxicological testing demonstrated no cocaine, cannabis, or …

Aortic endograft sizing in trauma patients with hemodynamic instability

OBJECTIVES To investigate changes in aortic diameter in hemodynamically unstable trauma patients and the implications for sizing of thoracic endovascular aortic repair (TEVAR) in patients with traumatic thoracic aortic injury (TTAI). METHODS We retrospectively evaluated all trauma patients that were admitted with hemodynamic instability (mean arterial pressure <95 mm Hg and a pulse >or=100 beats/min) and underwent computed tomography (CT) of the thorax and abdomen both at admission and at another moment (control CT scan), at the Yale New Haven Hospital between 2002 and 2009. The CT examinations were reviewed in a blinded fashion and the aortic diameter was measured at six different levels by a cardiovascular radiologist. Differences in aortic diameter between the initial CTs obtained in the trauma bay and the control CTs were compared using the paired Student t test. RESULTS Forty-three patients were identified, including 32 males. Mean age was 37 +/- 16 years, mean injury severity score was 26 +/- 15, the mean pulse and blood pressure were 122 beats/min and 103/63 mm Hg, respectively. Overall, the mean aortic diameter was significantly larger at the control CT examinations compared with the initial CT examinations while hemodynamically unstable, at all evaluated levels. Among patients with a pulse >or=130/min, the mean increase in aortic diameter was most consistent at the level of the mid descending thoracic aorta (DTA, +12.6%, P = .003) and at the level of the infrarenal aorta (+12.6%, P = .004). CONCLUSIONS The aortic diameter decreases dramatically in trauma patients with hemodynamic instability. This decrease in aortic diameter could theoretically lead to inaccurate aortic measurements and undersizing of the endograft in hemodynamically unstable TTAI patients requiring TEVAR. Further research is needed to better predict the actual aortic diameters in individual hemodynamically unstable patients requiring endovascular aortic repair.

Atypical aortic arch branching variants: A novel marker for thoracic aortic disease

OBJECTIVE To examine the potential of aortic arch variants, specifically bovine aortic arch, isolated left vertebral artery, and aberrant right subclavian artery, as markers for thoracic aortic disease (TAD). METHODS We screened imaging data of 556 patients undergoing surgery due to TAD for presence of aortic arch variations. Demographic data were collected during chart review and compared with a historical control group of 4617 patients. RESULTS Out of 556 patients with TAD, 33.5% (186 patients) demonstrated anomalies of the aortic arch, compared with 18.2% in the control group (P < .001). Three hundred seventy (66.5%) had no anomaly of the aortic arch. Bovine aortic arch emerged as the most common anomalous branch pattern with a prevalence of 24.6% (n = 137). Thirty-five patients (6.3%) had an isolated left vertebral artery, and 10 patients (1.8%) had an aberrant right subclavian artery. When compared with the control group, all 3 arch variations showed significant higher prevalence in patients with TAD (P < .001). Patients with aortic aneurysms and anomalous branch patterns had hypertension less frequently (73.5% vs 81.8%; P = .048), but had a higher rate of bicuspid aortic valve (40.8% vs 30.6%; P = .042) when compared with patients with aneurysms but normal aortic arch anatomy. Patients with aortic branch variations were significantly younger (58.6 ± 13.7 years vs 62.4 ± 12.9 years; P = .002) and needed intervention for the aortic arch more frequently than patients with normal arch anatomy (46% vs 34.6%; P = .023). CONCLUSIONS Aortic arch variations are significantly more common in patients with TAD than in the general population. Atypical branching variants may warrant consideration as potential anatomic markers for future development of TAD.

Open thoracic or thoracoabdominal aortic aneurysm repair after previous abdominal aortic aneurysm surgery

OBJECTIVE The purpose of this study was to provide insight into the incidence of thoracic and thoracoabdominal aortic aneurysm repair following previous infrarenal abdominal aortic aneurysm (AAA) surgery and to determine whether thoracic or thoracoabdominal aortic aneurysm repair after prior infrarenal AAA surgery is associated with higher mortality and morbidity rates. METHODS MEDLINE, Cochrane Library CENTRAL, and EMBASE databases were searched for relevant articles. Selected articles were critically appraised and meta-analyses were performed. RESULTS A total of 12.4% of patients with thoracic aortic aneurysms and 18.7% of patients with thoracoabdominal aortic aneurysms have had prior AAA surgery. The chance of developing a thoracic aortic aneurysm in patients with AAA is 2.2% and 2.5% for developing a thoracoabdominal aortic aneurysm. The mean time interval between prior AAA surgery and subsequent thoracoabdominal aortic aneurysm surgery or detection is 8.0 years with a wide variation between individuals. Surgery in these patients is technically feasible. The 30-day mortality of patients undergoing open thoracoabdominal aortic aneurysm repair does not significantly differ from patients without prior AAA surgery and the 30-day mortality is 11.8%. No data were available about mortality of patients with prior AAA repair undergoing thoracic aortic aneurysm surgery. Morbidity risks are higher in patients with thoracic or thoracoabdominal aortic aneurysms. Prior AAA repair was a significant risk factor for neurological deficit after thoracic or thoracoabdominal aortic aneurysms surgery with relative risks (RRs) of 11.1 (95% confidence interval [CI] 3.8-32.3, P value < .0001) and 2.90 (95% CI 1.26-6.65, P value = .008), respectively. Prior AAA repair was a significant risk factor for developing renal failure in patients undergoing thoracoabdominal aortic aneurysm repair (RR 3.47, 95% CI 1.74-6.91, P value = .0001). Determinants of the prognosis in these patients include distal aortic perfusion, distal extent of the landing zone of the graft, drainage of cerebrospinal fluid for thoracic aortic aneurysm repair and age, history of cardiac diseases, extent of the aneurysm, rupture, amount of estimated blood loss, aortic clamp time, and visceral ischemic times for thoracoabdominal aortic aneurysm repair. CONCLUSIONS A considerable group of patients with thoracic or thoracoabdominal aortic aneurysms have had prior AAA repair. The risk of postoperative morbidity is increased in these patients. Mortality appears to be similar for patients with thoracoabdominal aortic aneurysms. Patients with prior AAA repair undergoing thoracic or thoracoabdominal aortic aneurysm repair should be provided maximum care to protect their spinal cord and renal function.

Simultaneous sizing and preoperative risk stratification for thoracic endovascular aneurysm repair: Role of gated computed tomography

OBJECTIVES Risk factors are similar for the development of both thoracic aortic aneurysms (TAA) and other cardiovascular diseases. Coronary artery disease is highly prevalent in patients with TAA, with a reported prevalence of 30% to 70%. Knowledge of the underlying cardiac pathology can minimize perioperative risk and improve patient selection. This study investigated the feasibility of simultaneous assessment of thoracic aortic pathology and cardiac structures and function, including the coronary arteries, using electrocardiogram-gated 64-slice computed tomography (CT) angiography. METHODS ECG-gated 64-detector row CT examinations of 11 patients (8 men, 3 women; mean age, 67 +/- 16; range, 41-83 years) with thoracic aortic pathology, including aneurysms and dissections, were reviewed. Images were assessed for coronary artery disease, calcifications, cardiac function, and valve characteristics. Simultaneous assessment and measurements of thoracic aortic pathology were performed with the same scan. RESULTS All images of the patients could be successfully assessed for calcium scores, coronary artery stenoses, coronary artery anomalies, interventricular septal wall thickness, myocardial scar, left ventricular ejection fraction, muscle mass, and aortic and mitral valve calcification, mobility, and valve anatomy. Diagnostic image quality was also achieved in all patients for the underlying thoracic aortic disease. CONCLUSION This study introduces the feasibility of dynamic imaging of the thoracic aorta and cardiac structures and function, including the coronary arteries, with just one CT scan. The images could be successfully assessed for thoracic aorta pathology, cardiac disease, and extracardiac pathology. With further developments of CT scanners-and more detailed insight in the prognosis of patients based on ECG-gated CTA findings-this new technique may become the initial imaging modality for preoperative cardiac risk stratification in patients with TAAs or dissections.

Clinical Uses of Time-Resolved Imaging in the Body and Peripheral Vascular System

OBJECTIVE Time-resolved MR angiography (MRA) is a technique designed for fast vascular imaging. The purpose of this article is to introduce the multiple potential uses for time-resolved MRA in the body and peripheral vascular system in the hope that time-resolved MRA will become a more widely used technique. CONCLUSION Time-resolved MRA is a useful technique with many clinical applications.

Hemothorax Due to Rupture of Pulmonary Arteriovenous Malformation: An Interventional Emergency

Spontaneous hemothorax as a result of a ruptured pulmonary arteriovenous malformation (PAVM) is a life-threatening event and requires immediate interventional therapy. We present two patients who survived following emergent embolization. Definitive thoracentesis was delayed until embolization was performed. The tamponade provided by the hemothorax may have prevented exsanguination, suggesting to us that drainage of blood from the pleural space should be delayed until the PAVM has been treated. Hemorrhage from a PAVM may be the first manifestation of hereditary hemorrhagic telangiectasia. Genetic testing and screening for other family members should be considered.

Initial clinical experience with a new heparin‐coated chronic hemodialysis catheter

In this paper we wish to report our clinical experience with a new heparin‐coated dialysis catheter with a symmetric tip. Over a 16‐month period, 60 heparin‐coated Tal Palindrome™ catheters were placed in 57 patients. Catheter patency, catheter‐related complications, and reasons for catheter removal were recorded. The patients initial cause of end‐stage renal disease, underlying diseases, and site of access were recorded as well. Patients were specifically followed for development of heparin‐induced thrombocytopenia. Patient ages were 34–91 (average 66). Fifty‐four percent of patients had a history of diabetes. Sixty catheters were placed for a total of 5353 catheter‐days. The average catheter indwell time was 107 days (range of 2–381 days). Catheter‐related infection occurred in 6 patients over the study period, with a rate of 1.12/1000 catheter‐days. Bacteremia occurred in 3 patients with a rate of 0.56/1000 catheter‐days. Six catheters were removed or exchanged due to malfunction. There was no incidence of heparin‐induced thrombocytopenia. Initial clinical experience with the heparin‐coated Tal Palindrome™ hemodialysis catheter demonstrated safe, reliable use, and low infection rates.