Enhancement of the pulmonary arteries and thoracic aorta: comparison of a biphasic contrast injection and fixed delay protocol with a monophasic injection and a timing bolus protocol.

The definitive diagnosis of pulmonary embolism, a significant cause of morbidity and mortality, relies on imaging. In this study, we compare the conventional computed tomography pulmonary angiogram (CTPA) protocol to a double-rule out CT angiogram (DRO CTA) protocol in terms of vascular enhancement, radiation dose, and contrast volume delivered. The CTPA protocol involves injection of a timing bolus for localization of the pulmonary artery, whereas the DRO CTA protocol involves a biphasic contrast. We analyzed 248 consecutive CTPA studies and 242 consecutive DRO CTA studies. Vessel enhancement using region of interest (ROI) measurements, radiation dose delivered, and total contrast volume administered was recorded. The enhancement of all vessels measured was statistically significantly higher with the biphasic DRO CTA protocol than the CTPA protocol. The difference in mean vascular enhancement for the two protocols was greatest in the descending aorta (DA, P < 0.001) and least in the main pulmonary artery (MPA, P = 0.001). The percent of studies with vascular enhancement ≥250 Hounsfield units (HU) was significantly greater in all vascular beds except the MPA when the DRO CTA protocol was used. Studies performed with the DRO CTA protocol led to less radiation exposure and used less contrast than those performed with the CTPA protocol (P < 0.001 for both). According to the final radiology report, 35.08 % of studies in the CTPA group and 22.31 % of studies in the DRO CTA group were considered indeterminate (P = 0.001). In conclusion, the biphasic DRO CTA protocol leads to statistically significantly higher opacification of all pulmonary arterial and aortic vessels studied, with no greater delivery of radiation or contrast, than the monophasic CTPA protocol.

Minimal aortic injury of the thoracic aorta: imaging appearances and outcome.

The aim of this study is to describe the frequency, computed tomographic angiography (CTA) imaging appearance, management, and outcome of patients who present with minimal thoracic aortic injury. This retrospective study was Institutional Review Board-approved. Eighty-one patients with blunt traumatic aortic injuries (BTAI) were identified between 2004 and 2008, comprising 23 patients with minimal aortic injury (MAI) (mean age, 43.2 years ±18.2 years; 12 males and 11 females) and 58 patients with non-minimal aortic injury (mean age, 42.6 years ±22.7 years). CTA imaging was reviewed for each patient to differentiate those with MAI from those with non-MAI BTAI. Inclusion criteria for MAI on CTA were: post-traumatic abnormality of the internal contour of the aorta wall projecting into the lumen, intimal flap, intraluminal filling defect, intramural hematoma, and no evidence of an abnormality to the external contour of the aorta. Relevant follow-up imaging for MAI patients was also reviewed for resolution, stability, or progression of the vascular injury. The electronic medical record of each patient was reviewed and mechanism of injury, injury severity score, associated injuries, type and date of management, outcome, and days from injury to last medical consultation. Minimal aortic injury represented 28.4 % of all BTAI over the study period. Mean injury severity score (37.1), age (43.2 years), and gender did not differ significantly between MAI and non-MAI types of BTAI. Most MAI occurred in the descending thoracic aorta (16/23, 69 %). Without operative or endovascular repair, there was no death or complication due to MAI. One death occurred secondary to MAI (4.4 %) in a patient who underwent endovascular repair and surgical bypass, compared with an overall mortality rate of 8.6 % in the non-MAI BTAI group (p = 0.508). The most common CT appearance of MAI was a rounded or triangular intra-luminal aortic filling detect (18/23 patients, 78 %). In a mean of 466 days of clinical follow-up, no complications were observed in survivors treated without endovascular repair or operation. Minimal aortic injury is identified by multi-detector row CT in more than a quarter of cases of BTAI and has a low mortality. Conservative management is associated with an excellent outcome.

State of the art: technologies for computed tomography dose reduction.

The utilization of computed tomography (CT) in the emergency department has grown rapidly in the last decade, driven by strong evidence supporting its effectiveness in the rapid diagnosis of an increasing range of diseases. Concerns have been raised about potential cancer induction caused by the increased use of CT and the high radiation dose associated with some multidetector row CT examinations. Recent research into protocol design and new CT scanner technologies enable high-quality examinations to be performed with a significant reduction in radiation dose. These advances are discussed, with emphasis on their application to emergency radiology.

Uterine diverticulum.

BACKGROUND: Uterine diverticula complicating pregnancy rarely are reported and should be differentiated from sacculation of pregnancy and other pelvic masses. CASE: A primigravida presented for a routine second-trimester anatomical survey ultrasound examination at 22 weeks of gestation. She initially was thought to have a bicornuate, bicolic uterus with bulging membranes. However, on examination, one normal-appearing cervix was found, and no membranes were visible. Magnetic resonance imaging demonstrated a posterolateral uterine diverticulum. At 31 weeks of gestation, she had premature rupture of membranes and onset of labor. Delivery by cesarean was performed, and the presence of a uterine diverticulum was confirmed. CONCLUSION: Uterine diverticula are rare anomalies in the pregnant uterus and should be considered in the differential diagnosis of a fluid-filled pelvic mass. With close observation, successful pregnancy outcome can be achieved.

Multidetector computed tomography pulmonary angiography: does arm position affect pulmonary artery enhancement?

OBJECTIVE: To evaluate whether arm position affects pulmonary artery enhancement in computed tomographic pulmonary angiography (CTPA). METHODS: Study protocol had local ethics committee approval. Eighty-six patients who received 16 detector row CTPA for suspected pulmonary embolism were scanned with their contrast-injected arm resting at their side and compared with 94 patients who were scanned with both arms resting above their head. Two radiologists assessed pulmonary artery enhancement with a region-of-interest measurement of the main pulmonary artery density, scored the degree of beam-hardening artifact arising from the superior vena cava (SVC) and from the dependent arm that crossed the pulmonary arteries (1 = no artifact, 5 = artery obscured), and measured the degree of central venous compression of the injected veins at the thoracic inlet. A 2-tailed t test was performed to compare pulmonary artery density and central venous compression. RESULTS: There was no difference in pulmonary artery enhancement between the 2 arm positions. Mean density of contrast in the main pulmonary artery was 329 Hounsfield units (HU) (95% confidence interval (CI), 310-350) in the arm-down group, compared with 325 HU (95% CI, 306-346) in the arm-up group (P = 0.65). Greater compression of the central veins occurred in the arm-up group (48.5%; 95% CI, 42.3%-54.8%) than in the arm-down group (22.3%; 95% CI, 16.8%-27.8%) (P < 0.05). There was also more beam hardening arising from contrast in the SVC in the arm-up group (P < 0.0001). CONCLUSIONS: Arm position does not affect pulmonary arterial enhancement during CTPA. There was greater central venous compression and more beam-hardening artifact arising from the SVC when the arm was held above the head.

Computed tomographic and magnetic resonance features of gynecologic abnormalities in women presenting with acute or chronic abdominal pain.

Advances in technology and improved availability have led to increased use of computed tomography (CT) and magnetic resonance imaging (MRI) to evaluate women presenting to the emergency department or to their primary care provider with abdominal and/or pelvic pain. Computed tomographic examinations are often performed to evaluate the presence of appendicitis or renal stone disease. However, gynecologic abnormalities are frequently identified on these examinations. Although ultrasound remains the primary modality by which complaints specific to the pelvis are evaluated, in many instances, CT and MRI imaging occurs before sonographic evaluation.Historically, because of cost, radiation exposure, and relative ease of use, ultrasound examinations have preceded all other imaging modalities when evaluating pelvic disorders. However, as CT and MRI technology have improved, their use in diagnosing causes of pelvic pain has become equal to that of ultrasound. In some cases, primarily because of historic comfort with sonographic evaluation, gynecologic abnormalities originally diagnosed on CT or MRI may be immediately and unnecessarily reevaluated by ultrasound. For a woman in her reproductive years, the most common adnexal masses are physiological cysts, endometriomas, and cystic teratomas. Although lesions are often asymptomatic and incidentally detected, they can present with pain, and they increase the risk of ovarian torsion. Common causes of chronic pelvic pain in this population include leiomyomata and adenomyosis. In postmenopausal women, ovarian carcinoma, which often does not present clinically until a late stage, has to be included in the differential diagnosis of adnexal masses. If a gynecologic pathology is discovered on CT or MRI, an immediate follow-up ultrasound need not be pursued if the lesion can be characterized as benign, needing immediate surgical intervention, or a variant of normal anatomy. If, on the other hand, findings demonstrate a mass that either is uncharacteristic of a benign lesion, has an indeterminate risk for malignancy, or demonstrates suspicious characteristics for malignancy (such as enhancing mural nodules), further evaluation by serial ultrasound, biochemical marker, and/or CT or MRI is warranted. The purpose of this review is to present a series of commonly encountered gynecologic abnormalities with either CT or MR to make radiologists more familiar with gynecologic pathology on CT and MRI.

Personal computer-based PACS display system: comparison with a dedicated PACS workstation for review of computed radiographic images in rheumatoid arthritis.

RATIONALE AND OBJECTIVES: The authors' purpose was to investigate the reliability of a personal computer (PC)-based display system compared with a workstation in the evaluation of rheumatoid arthritis on computed radiographs of the hands. MATERIALS AND METHODS: Two radiologists on two occasions independently scored randomized computed radiographs of individual joints of the hands from 23 patients with rheumatoid arthritis and 14 control subjects. Each joint was scored from 0 (definitely normal) to 30 (severe disease) for each of four variables: soft-tissue swelling, osteopenia, erosions, and joint space narrowing. The observations were replicated on a picture archiving and communication system workstation and a PC. Intraobserver and interobserver reliability were calculated, as was the difference in scores between the two systems. The null hypothesis was that there was no difference between the workstation and the PC. RESULTS: The intraobserver reliability for normal versus abnormal joints was 73% with the workstation and 79% with the PC. The intraobserver reliability for workstation versus PC was 83%. There was moderate interreader reliability for both platforms (average kappa statistic, 0.46 [workstation] vs 0.45 [PC]). Small differences in scores between platforms are probably due mostly to the ordinal nature of the scoring system. CONCLUSION: For evaluating computed radiographs of the hands in early rheumatoid arthritis, a PC-based system provides results similar to those obtained with a workstation, at considerably reduced cost.

Gossypiboma: tales of lost sponges and lessons learned.

OBJECTIVE: To review the details surrounding cases of patients found to have retained laparotomy sponges after surgical procedures and share policy changes that have led to process improvements at one academic medical center. DESIGN: Retrospective medical record review as part of a quality improvement process. SETTING: Single academic medical center. PATIENTS: Patients identified through the quality improvement process as having had retained foreign bodies after surgery. CONCLUSIONS: Sentinel events such as retained foreign bodies after surgery require intensive review to identify systems problems. This can lead to protocol changes to improve the process. After a series of incidents, protocol changes at our institution have led to no further incidents of retained foreign bodies.

High-resolution CT findings of bronchiolitis obliterans syndrome after hematopoietic stem cell transplantation.

PURPOSE: To describe the high-resolution computed tomography (CT) findings occurring in bronchiolitis obliterans syndrome (BOS) after hematopoietic stem cell transplantation (HSCT) and to determine the relationship between pulmonary function tests (PFTs) and air trapping detected on expiratory CT. MATERIALS AND METHODS: The high-resolution CT scans of 33 patients who underwent HSCT and subsequently developed BOS were evaluated by 2 observers blinded to PFT results. Scans were ranked for degree of air trapping and scored for findings of bronchial wall thickening, bronchiectasis, and centrilobular opacities. Air-trapping rank was correlated with the degree of airflow obstruction as determined by PFTs. RESULTS: The ranking of air trapping correlated significantly with 1-second forced expiratory volume (P=0.001), 1-second forced expiratory volume/forced vital capacity (P<0.001), residual volume (P<0.001), carbon monoxide diffusion capacity (P=0.023), but not forced vital capacity (P=0.14) or total lung capacity (P=0.07). Bronchial wall thickening occurred in 73.0%, predominantly in lower lobes (P=0.007), but was mild. Bronchiectasis occurred in 42.4% and centrilobular opacities in 39.4%. CONCLUSIONS: In BOS developing after HSCT, air trapping is the principal finding on CT, and its severity correlates with PFTs. Bronchial wall thickening is common, but almost always mild; bronchiectasis and centrilobular opacities occur in less than half of cases and are also mild.