Mayil S. Krishnam

Image quality and diagnostic accuracy of unenhanced SSFP MR angiography compared with conventional contrast-enhanced MR angiography for the assessment of thoracic aortic diseases

ObjectivesThe purpose of this study was to determine the image quality and diagnostic accuracy of three-dimensional (3D) unenhanced steady state free precession (SSFP) magnetic resonance angiography (MRA) for the evaluation of thoracic aortic diseases.MethodsFifty consecutive patients with known or suspected thoracic aortic disease underwent free-breathing ECG-gated unenhanced SSFP MRA with non-selective radiofrequency excitation and contrast-enhanced (CE) MRA of the thorax at 1.5u2009T. Two readers independently evaluated the two datasets for image quality in the aortic root, ascending aorta, aortic arch, descending aorta, and origins of supra-aortic arteries, and for abnormal findings. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were determined for both datasets. Sensitivity, specificity, and diagnostic accuracy of unenhanced SSFP MRA for the diagnosis of aortic abnormalities were determined.ResultsAbnormal aortic findings, including aneurysm (nu2009=u200947), coarctation (nu2009=u200914), dissection (nu2009=u200912), aortic graft (nu2009=u20096), intramural hematoma (nu2009=u200911), mural thrombus in the aortic arch (nu2009=u20091), and penetrating aortic ulcer (nu2009=u20099), were confidently detected on both datasets. Sensitivity, specificity, and diagnostic accuracy of SSFP MRA for the detection of aortic disease were 100% with CE-MRA serving as a reference standard. Image quality of the aortic root was significantly higher on SSFP MRA (Pu2009<u20090.001) with no significant difference for other aortic segments (Pu2009>u20090.05). SNR and CNR values were higher for all segments on SSFP MRA (Pu2009<u20090.01).ConclusionOur results suggest that free-breathing navigator-gated 3D SSFP MRA with non-selective radiofrequency excitation is a promising technique that provides high image quality and diagnostic accuracy for the assessment of thoracic aortic disease without the need for intravenous contrast material.

Cystic adventitial disease of the popliteal artery: features on 3T cardiovascular magnetic resonance

Cystic adventitial disease (CAD) of the popliteal artery is a rare vascular disease of unknown etiology in which a mucin-containing cyst develops in the adventitial layer of the artery. We report the case of a 26-year-old male with CAD of the right popliteal artery diagnosed non-invasively with 3 Tesla cardiovascular magnetic resonance and confirmed on post-operative histopathology.

Coronary artery to pulmonary artery fistulae with multiple aneurysms: radiological features on dual-source 64-slice CT angiography

Coronary artery fistula is a rare vascular anomaly in which there is abnormal communication between the coronary artery and the great vessels or cardiac chambers. We report the case of a 66-year-old man with two separate coronary artery to pulmonary artery fistulas (one of which demonstrated multiple aneurysms), which were diagnosed on dual-source 64-slice coronary CT and reconfirmed by coronary catheter angiography.

Left ventricular ejection fraction using 64-slice CT coronary angiography and new evaluation software: initial experience.

The purpose of this study was to evaluate the feasibility and reliability of software-based quantification of left ventricular function using 64-slice CT coronary angiography. Data were collected from 26 subjects who underwent a 64-slice coronary CT angiography study. Two volumetric data sets at end diastole and end systole were reconstructed from each scan by means of retrospective electrocardiogram gating. Data sets were evaluated with a prototype of now commercially available software (Syngo Circulation I; Siemens Medical Solutions, Erlangen, Germany), which automatically segments the blood volume in the left ventricle after the user defines the mitral valve plane and any point within the ventricle. After segmentation of the blood pool in end systole and end diastole, the software automatically measures end systolic and end diastolic volume and calculates stroke volume and ejection fraction (EF). Two readers processed all CT data sets twice to assess for intra- and inter-observer variation. In addition, CT EF measurements were compared with those obtained by clinical echocardiography. Intra-observer variation for the calculated EF with CT were 13.6% and 15.6% for Readers 1 and 2, respectively. No significant difference in left ventricular functional parameters on CT existed between the readers (p > 0.05). A Bland-Altman plot revealed a slight mean difference between EF measurements on CT and echocardiography, with all differences falling within two standard deviations of the mean in the setting of wide limits of agreement. In conclusion, assessment of left ventricular EF from CT coronary data using the new analysis software is rapid and easy. The software is user-friendly and provides good reproducibility for EF measurements with CT.

Detection of myocardial perfusion abnormalities: standard dual-source coronary computed tomography angiography versus rest/stress technetium-99m single-photo emission CT

We compared coronary dual-source computed tomography angiography (corDSCTA) with technetium-99m single-photon emission computed tomography (SPECT) for the detection of myocardial perfusion abnormalities. Fifty-five consecutive patients underwent both gated myocardial perfusion SPECT and corDSCTA, the latter during a single arterial-phase injection of contrast agent. The perfusion defects visualised by corDSCTA correlated with the findings of rest/stress SPECT. Abnormal findings on stress SPECT, which were due to either ischaemia or infarct, were found in 24 patients. In comparison to SPECT at rest, corDSCTA detected perfusion defects with a sensitivity and specificity of 100% and 78%, respectively. Compared to SPECT at stress, the sensitivity and specificity values of corDSCTA were 83.3% and 90.3%, respectively. On corDSCTA , the average attenuation values of perfusion defects that corresponded to chronic infarcts (-8.5+/-22.2 HU) were significantly lower (p = 0.002) than those of non-infarct-related perfusion defects (43.1+/-17.5 HU). Using rest/stress SPECT is the gold standard for the diagnosis of myocardial ischaemia, corDSCTA was able to diagnose ischaemic disease (defined as the presence of high-grade stenotic CAD (>or=50% luminal narrowing)) with a sensitivity and specificity of 59% and 89%, respectively, in patients with no known history of myocardial infarction (n = 4). Thus, corDSCTA may serve as a diagnostic tool for the detection of perfusion abnormalities (first) visualised by SPECT. There appears to be a limited correlation between coronary stenotic disease and SPECT findings.

Congenital heart diseases: post-operative appearance on multi-detector CT—a pictorial essay

Echocardiography is considered as an initial imaging modality of choice in patients with congenital heart disease (CHD), and magnetic resonance (MR) imaging is preferred for detailed functional information. Multi-detector computed tomography (CT) plays an important role in clinical practice in assessing post-operative morphological and functional information of patients with complex CHD when echocardiography and MR imaging are not contributory. Radiologists should understand and become familiar with the complex morphology and physiology of CHD, as well as with various palliative and corrective surgical procedures performed in these patients, to obtain CT angiograms with diagnostic quality and promptly recognise imaging features of normal post-operative anatomy and complications of these complex surgeries.

CT-guided percutaneous transpulmonary adrenal biopsy — a technical note

CT-guided percutaneous adrenal biopsy is commonly performed using a posterior or trans-abdominal approach. However, trans-abdominal access to the gland may not be technically feasible in some patients. In our case, CT-guided transthoracic percutaneous biopsy of the adrenal gland was performed with technical success, identifying the tumour. To the best of our knowledge, there has been no previous case describing this transpulmonary approach in the literature.

Computed tomography angiography of lower extremities in the emergency room for evaluation of patients with gunshot wounds

AbstractObjectiveTo assess the role of CT angiography in the evaluation of patients with lower extremity gunshot wounds in the emergency room.Materials and methodsEighty patients (73 male, 7 female, mean age 26xa0years) underwent CT angiography for the evaluation of lower extremity gunshot injuries. Imaging was conducted on the basis of standardized protocols utilizing 16-slice and 64-slice multidetector systems and images were qualitatively graded and assessed for various forms of arterial injury.ResultsCT angiography findings indicative of arterial injury were observed in 24 patients (30xa0%) and a total of 43 arterial injuries were noted; the most common form was focal narrowing/spasm (nu2009=u200916, 37.2xa0%); the most common artery involved was the superficial femoral artery (nu2009=u200912, 50xa0%). In qualitative assessment of images based on a 4-point grading system, both readers considered CT angiography diagnostically excellent (grade 4) in most cases. Surgical findings were consistent with CT angiography and follow-up of patients’ medical records showed no arterial injuries in patients with normal findings on initial imaging.ConclusionOur findings demonstrate that CT angiography is an effective imaging modality for evaluation of lower extremity gunshot wounds and could help limit more invasive procedures such as catheter angiography to a select group of patients.Key Points• CT angiography efficiently evaluates lower extremity gunshot wounds.n • CT angiography provides image quality sufficiently reliable for assessment of gunshot injuries.n • CT angiography could help limit invasive procedures to select patients.

MR angiography of midaortic syndrome - eScholarship

A 12-year-old boy presented with hypertension and intermittent lower extremity claudication. Breath-hold high spatial resolution MRA at 3.0xa0T (gradient recalled echo sequence; 10xa0ml of Magnevist) revealed abdominal aortic coarctation (Fig.xa01, thin long arrow), severely narrowed right renal artery and atrophy of the ipsilateral kidney (Fig.xa01b, arrowhead), and hypertrophied inferior mesenteric artery (Fig.xa01a, thick short arrow) feeding the superior mesenteric artery (Fig.xa01a, thin short arrow) through the arc of Riolan (Fig.xa01a, arrowhead). The child had previously undergone placement of an aorto-aortic graft (Fig.xa01, thick long arrow). n n n nFig.xa01 n n3-D volume-rendered MR angiograms (Vitrea 3.6; Vital Images, Minneapolis, MN) n n n nMidaortic syndrome (MAS) is a rare disease caused by segmental narrowing of the abdominal or distal descending thoracic aorta associated with concomitant stenoses involving the renal (63%) and visceral (33%) arteries [1]. MAS can be congenital or acquired caused by giant cell or Takayasu arteritis, retroperitoneal fibrosis, Williams syndrome, fibromuscular dysplasia, neurofibromatosis, and mucopolysaccharidosis [1, 2]. Noninvasive diagnosis is made by MRA or CT angiography [2]. Surgical bypass grafting is the optimal method of treatment [1].