Low-high and high-low biphasic injection forms in computed tomography examinations of the upper abdomen

Purpose: To analyze the influence of different biphasic and monophasic injection rate protocols in abdominal computed tomography (CT).

Material and Methods: A randomized, consecutive, parallel group study was designed and conducted in 60 patients studied with the same CT helical protocol. Patients were randomly distributed into three groups: (A) monophasic (120 ml at 2.5 ml/s); (B) low-high biphasic (120 ml, first 60 ml at a rate of 2 ml/s, the other 60 ml at 2.5 ml/s); and (C) high-low biphasic (120 ml, first 60 ml at a rate of 2.5 ml/s, the other 60 ml at 2 ml/s). All patients were injected with 300 mg I/ml non-ionic contrast media at a fixed delay time of 55 s. Contrast enhancement efficacy was evaluated by attenuation coefficient measurements.

Results: Although non-significant, monophasic protocol enhancements were higher than biphasic protocol enhancements in all measurements except aortic bifurcation (p = 0.003). At this level, biphasic protocols obtained an increased mean enhancement from 7.6% to 2.5% compared to monophasic protocols.

Conclusion: Monophasic contrast agent injection in helical CT of the upper abdomen produces a higher enhancement of parenchymal and venous structures. No significant difference was observed between low-high and high-low biphasic protocols.     

Effect of contrast material pushed with saline solution using dual injection on enhancement of aorta, portal vein, and liver parenchyma in multislice CT of the liver

We evaluated the effect of the enhancement value of the abdominal aorta, portal vein, and liver parenchyma by the saline flush technique. One hundred eight patients who underwent multislice CT of the liver were randomly divided into four groups: 100 ml of contrast material (Iomeprol 300 mgI/ml or 350 mgI/ml) only and 100 ml of contrast material (300 mgI/ml or 350 mgI/ml) flushed with 50 ml of saline solution at a rate of 5 ml/sec. The saline flush technique demonstrated statistically significantly greater portal enhancement. Therefore, we consider that this technique contributes to the visualization of three-dimensional CT portography.     

Noninvasive multidetector computed tomography enterography in patients with small-bowel Crohn's disease: is a 40-second delay better than 70 seconds?

Background: Multidetector computed tomography (MDCT) enterography combines neutral enteric contrast with intravenously administered contrast material. The optimal intravenous (IV) contrast material protocol has still not been established.

Purpose: To determine the optimal delay time to image patients with small-bowel Crohn's disease during MDCT enterography.

Material and Methods: After oral administration of 1350 ml of neutral contrast medium, 26 patients with small-bowel Crohn's disease underwent MDCT enterography; scans were obtained 40 s (enteric phase) and 70 s (parenchymal phase) after IV administration of 100 ml of iodinated contrast material. Three radiologists, blinded to clinical and pathological findings, independently and retrospectively evaluated each scan in two separate reading sessions for the presence or absence of CT features of Crohn's disease activity. The interobserver agreement was evaluated, and the efficacy of each phase in detecting active disease in the terminal ileum for each reader was determined. The gold standard was pathology (n = 13), endoscopy (n = 3), and clinical evaluation (n = 10).

Results: No statistically significant difference was present between the enteric and the parenchymal phase for each reader in each segment regarding the presence or absence of CT features of Crohn's disease. The interobserver agreement for the presence of five main features of active Crohn's disease in the terminal ileum ranged from poor to excellent. The sensitivity, specificity, negative predictive value, positive predictive value, and accuracy for active Crohn's disease in the terminal ileum ranged from 40 to 90%, 88 to 100%, 70 to 94%, 44 to 100%, and 69 to 96%, respectively. There was no statistical difference between the two phases for each reader.

Conclusion: MDCT enterography in patients with suspected active Crohn's disease can be obtained at either 40 s or 70 s after IV contrast material.     

Comparison of Gd-DTPA-induced signal enhancements in rat brain C6 glioma among different pulse sequences in 3-Tesla magnetic resonance imaging

Background: T1-shortening contrast media are routinely used in magnetic resonance (MR) examinations for the diagnosis of brain tumors. Although some studies show a benefit of 3 Tesla (T) compared to 1.5T in delineation of brain tumors using contrast media, it is unclear which pulse sequences are optimal.

Purpose: To compare gadopentetate dimeglumine (Gd-DTPA)-induced signal enhancements in rat brain C6 glioma in the thalamus region among different pulse sequences in 3T MR imaging.

Material and Methods: Five rats with a surgically implanted C6 glioma in their thalamus were examined. T1-weighted brain images of the five rats were acquired before and after Gd-DTPA administration (0.1 mmol/kg) using three clinically available pulse sequences (spin echo [SE], fast SE [FSE], fast spoiled gradient echo [FSPGR]) at 3T. Signal enhancement in the glioma (E_T) was calculated as the signal intensity after Gd-DTPA administration scaled by that before administration. Pulse sequences were compared using the Tukey-Kramer test.

Results: E_T was 1.12±0.05 for FSE, 1.26±0.11 for FSPGR, and 1.20±0.11 for SE. FSPGR showed significantly higher signal enhancement than FSE and comparable enhancement to SE.

Conclusion: FSPGR is superior to FSE and comparable to SE in its ability to delineate rat brain C6 glioma in the thalamus region.     

Do contrast media (iomeprol, gadopentetate dimeglumine) deteriorate ischemia/reperfusion injury of the liver?

Background: Hepatic microcirculation is a main determinant of reperfusion injury and graft quality in liver transplantation. One of the important diagnostic procedures to recognize reperfusion failure is contrast-enhanced computed tomography or magnetic resonance imaging.

Purpose: To examine the additional effect of contrast media (iomeprol and gadopentetate dimeglumine) on hepatic microcirculation and hepatic cellular damage in the phase of early ischemia/reperfusion injury of the rat liver.

Material and Methods: The partial warm ischemia-reperfusion injury model of rat liver was used. Microcirculation and leukocyte-endothelium interaction were measured by intravital microscopy. Hepatic cellular damage was indicated by liver enzyme activity in the sera. The evaluation parameters were measured at baseline and at 30, 60, and 90 min after reperfusion. The contrast media (iomeprol group, n = 6; gadopentetate dimeglumine group, n = 6) or Ringer's solution (control group, n = 8) were applied after 30 min of reperfusion.

Results: No additional injury to the ischemia/reperfusion injury of the liver after intravenous application of radiographic contrast media was found. Some protective effect was even recorded after application of iodinated contrast media.

Conclusion: The use of contrast media during diagnostic procedure of the liver seems to be relatively safe, even in the stage of early reperfusion after liver transplantation.     

Accessory renal artery stenosis and hypertension: are these correlated? Evaluation using multidetector-row computed tomographic angiography

Background: Renal artery stenosis may produce hypertension, and this condition is referred to as renovascular hypertension (RVH).

Purpose: To evaluate, by using multidetector-row spiral computed tomographic angiography (MDCTA), whether a relationship between accessory renal artery stenosis and hypertension may be hypothesized.

Material and Methods: 214 patients (142 males, 72 females; mean age 66 years) who had previously undergone an MDCTA to study the abdominal vasculature were retrospectively studied. Patients with renal artery stenosis (RAS) were excluded from this analysis. The patients were studied by means of a four-detector-row CT, and scans were obtained after intravenous bolus administration of 110-140 ml of a nonionic contrast material with a 3-6 ml/s flow rate. As a second step, by means of statistical analysis, hypertension data were compared with findings of accessory artery stenosis. Two radiologists first independently reviewed the MDCTA images and then, in case of disagreement, in consensus. Interobserver agreement was calculated for all measurements.

Results: The overall number of detected accessory renal arteries was 74 in 56 of the 214 patients. Accessory renal artery stenosis was detected in 21 of the 56 patients. There was a difference in the prevalence of hypertension between patients with (n = 21) and without (n = 35) accessory renal artery stenosis (P = 0.0187). Interobserver agreement was good (kappa value 0.733).

Conclusion: Any statistical association between the presence of accessory renal artery stenosis and hypertension could not be disclosed. However, accessory renal artery stenosis, detected by MDCTA, is an important pathological sign that the radiologist has to assess in the light of its possible association with hypertension.     

Attempts to improve absolute quantification of cerebral blood flow in dynamic susceptibility contrast magnetic resonance imaging: a simplified T1-weighted steady-state cerebral blood volume approach

Background: Attempts to retrieve absolute values of cerebral blood flow (CBF) by dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) have typically resulted in overestimations.

Purpose: To improve DSC-MRI CBF estimates by calibrating the DSC-MRI-based cerebral blood volume (CBV) with a corresponding T1-weighted (T1W) steady-state (ss) CBV estimate.

Material and Methods: 17 volunteers were investigated by DSC-MRI and ¹³³Xe SPECT. Steady-state CBV calculation, assuming no water exchange, was accomplished using signal values from blood and tissue, before and after contrast agent, obtained by T1W spin-echo imaging. Using steady-state and DSC-MRI CBV estimates, a calibration factor K = CBV(ss)/CBV(DSC) was obtained for each individual. Average whole-brain CBF(DSC) was calculated, and the corrected MRI-based CBF estimate was given by CBF(ss) = K×CBF(DSC).

Results: Average whole-brain SPECT CBF was 40.1±6.9 ml/min·100 g, while the corresponding uncorrected DSC-MRI-based value was 69.2±13.8 ml/min·100 g. After correction with the calibration factor, a CBF(ss) of 42.7±14.0 ml/min·100 g was obtained. The linear fit to CBF(ss)-versus-CBF(SPECT) data was close to proportionality (R = 0.52).

Conclusion: Calibration by steady-state CBV reduced the population average CBF to a reasonable level, and a modest linear correlation with the reference ¹³³Xe SPECT technique was observed. Possible explanations for the limited accuracy are, for example, large-vessel partial-volume effects, low post-contrast signal enhancement in T1W images, and water-exchange effects.     

Hyperperfusion on perfusion computed tomography following revascularization for acute stroke

Purpose: To describe the findings of hyperperfusion on perfusion computed tomography (CT) in four patients following revascularization for acute stroke.

Material and Methods: In 2002-2003, among a series of 6 patients presenting with an acute stroke and treated with intra-arterial thrombolysis, we observed the presence of hyperperfusion in 3 patients on the follow-up CT perfusion. We included an additional patient who was treated with intravenous thrombolysis and who had hyperperfusion on the follow-up CT perfusion. We retrospectively analyzed their CT perfusion maps. Cerebral blood volume (CBV) and cerebral blood flow (CBF) maps were compared between the affected territory and the normal contralateral hemisphere.

Results: In the four patients, the mean CBV and CBF were 3.6±2.0 ml/100 g and 39±25 ml/100 g/min in the affected territory compared to the normal side (mean CBV = 2.7±2.1 ml/100 g, mean CBF = 27±23 ml/100 g/min). There was no intracranial hemorrhage in the hyperperfused territories. At follow-up CT, some hyperperfused brain areas progressed to infarction, while others retained normal white to gray matter differentiation.

Conclusion: CT perfusion can demonstrate hyperperfusion, which can be seen in an ischemic brain territory following recanalization.     

Evaluation of hypervascular hepatocellular carcinoma in cirrhotic liver by means of helical CT: comparison of different contrast medium concentrations within the same patient

PURPOSE: To compare enhancement of the aorta, portal vein, liver, and tumor with contrast medium of a higher iodine concentration to that with one of a standard iodine concentration for liver dynamic CT within the same patient with known liver cirrhosis and hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Fifty-three patients with known cirrhosis and HCC underwent repeat computed tomographic (CT) examinations within three months, the first with either 300 (n=26) or 370 mgI/ml (n=27) of nonionic contrast material. In the second examination, only concentration was altered. In 28 patients, weight was equal to or more than 65 kg, and in 25 patients it was less than 65 kg. The CT numbers (HU) of the aorta, portal vein, liver, and tumor were obtained, and CT attenuation was compared between the two concentration studies. The degree of enhancement was scored qualitatively. RESULTS: Mean enhancement values of the aorta, liver, portal vein, and tumor were greater with the 370 mgI/ml injections than with the 300 mgI/ml injections throughout the study. In visual analysis, the difference in aortic, portal venous, liver, and tumor enhancement was not statistically significant between the two groups in patients weighing less than 65 kg. However, in patients weighing 65 kg or more, strong aortic and portal venous enhancement (rated as good or excellent) occurred more frequently with the 370 mgI/ml injections than with the 300 mgI/ml injections. CONCLUSION: Higher contrast enhancement was achieved in patients who received 370 mgI/ml of contrast material, resulting in better tissue contrast between liver parenchyma and HCCs. However, this difference was not visually significant in patients weighing less than 65 kg.     

Split renal function in patients with suspected renal artery stenosis: a comparison between gamma camera renography and two methods of measurement with computed tomography

Purpose: To validate a method for calculating split renal function from computed tomography (CT) compared with gamma camera renography, and to test a new method for the measurement based on a volume-rendering technique.

Material and Methods: Thirty-eight patients, aged 65.7±11.6 (range 37.8-82.1) years, who had undergone both CT angiography and gamma camera renography for a suspected renal artery stenosis were included in this study. Split renal function was calculated from the CT examinations by measuring area and mean attenuation in the image slices of the kidneys, and also by measuring volume and mean attenuation from a 3D reconstruction of the kidneys. Gamma camera renography with ^99mTc-MAG3 with or without captopril enhancement was used as a reference.

Results: The 2D CT method had good correlation with renography (r = 0.93). Mean difference was 4.7±3.6 (0-12) percentage points per kidney. There was also excellent correlation between the two CT methods (r = 1.00).

Conclusion: CT is equivalent to renography in determining split renal function, and the measurement from the CT examination can be made more quickly and equally accurately with a 3D technique.     

Effect of informed consent for intravascular contrast material on the level of anxiety: how much information should be given?

Purpose: To compare the effect of two different informed consent forms on patients' anxiety level prior to intravenous contrast material (IVCM) injection.

Material and Methods: Two different informed consent forms were randomly given to 265 consecutive patients referred for either intravenous pyelography or computed tomography requiring IVCM injections. Form 1 had brief information, including only the common risks and risk factors associated with IVCM, while Form 2 had more comprehensive information. Before being presented with the two different informed consent forms, 191 of the 265 patients filled out two other forms evaluating: 1: How they felt in that particular situation/moment (STAI-T); and 2: How they felt independently of the situation or condition at that moment (STAI-S). After the patients were informed, the STAI-T (measuring how they felt in that particular situation) was filled out once more to see if the anxiety level had changed.

Results: The anxiety level for 88 patients receiving Form 1 decreased after they were given the informed consent (P = 0.033). However, among the 103 patients receiving Form 2, the anxiety level showed a significant increase (P = 0.001) compared to the values obtained before Form 2 was given.

Conclusion: These results indicate that informed consent, including brief information about the risk factors and potential adverse reactions of IVCM, reduces anxiety level, while detailed information before the procedure increases the anxiety level.     

Volumetric coronary angiography using the 256-detector row computed tomography scanner: comparison in vivo and in vitro with porcine models

Purpose: To investigate the feasibility of volumetric cine imaging in human cardiac studies by comparing in vivo and in vitro coronary angiography using a 256-detector row computed tomography (CT) without ECG gating.

Material and Methods: The left and right coronary arteries of two domestic pigs were scanned in vivo and in vitro in cine mode using the 256-detector row CT. The device scanned approximately 100 mm in the cranio-caudal direction with one rotation, with a slice thickness of 0.5 mm.

Results: The coronary arteries could be observed to the third-degree branches in vitro, but could be visualized clearly only to the proximal portion (first-degree or second-degree branches) in vivo.

Conclusion: Application of cardiac volumetric cine imaging with 256-detector row CT may be a promising means of obtaining diagnostic information and has potential for adoption to human studies.     

What are radiologists doing to prevent contrast-induced nephropathy (CIN) compared with measures supported by current evidence? A survey of European radiologists on CIN associated with computed tomography

Background: Contrast-induced nephropathy (CIN) is a serious complication of the use of iodinated contrast media (CM), and is associated with increased morbidity and mortality.

Purpose: To investigate whether radiologists take sufficient measures to prevent CIN in computed tomography (CT).

Material and Methods: 2005 survey of 509 European radiologists who had ≥3 years' experience and performed ≥50 CT scans/week.

Results: The most common methods used to identify patients at risk of CIN were renal function measurements (64%), clinical judgment (55%), and patient questionnaires (31%); 9% made no routine attempt to identify at-risk patients. The most common preventive protocols used in at-risk patients included: intravenous (i.v.) saline volume repletion (59%) or oral hydration (52%) before/after CT; use of low-osmolar CM (LOCM; 40%) or isosmolar CM (IOCM; 36%); and N-acetylcysteine (20%); 8% used no hydration regimen. While 78% of respondents used ≤100 ml of CM in high-risk patients, 14% used ≤150 ml, and 9% set no volume limit. For 57% of respondents, osmolality was the most important attribute in choosing an iodinated CM in at-risk patients; 41% agreed that CIN risk is lower with IOCM versus LOCM (31% disagreed).

Conclusion: A European radiologist survey identified a need for increased implementation of evidence-based protocols to improve CIN prevention: routine identification of at-risk patients; withdrawal of nephrotoxic drugs; use of volume repletion regimens; lowest possible volume of CM; and appropriate CM.     

Optimal iodine dose for 3-dimensional multidetector-row CT angiography of the liver

Purpose

To clarify the optimal iodine dose of contrast material for 3-dimensional multidetector-row CT angiography (3D-MDCTA) of the venous vasculature of the liver using volume rendering technique.

Materials and methods

This study included 103 patients who were randomly assigned to 5 contrast-enhanced MDCT protocol groups with different body-weight-tailored doses of contrast material: 500, 600, 630, 650, and 700 mgI/kg body weight. The arterial, portal, and hepatic parenchymal phases were obtained to evaluate enhancement values of the aorta, portal vein, and hepatic vein. Visualization of the portal and hepatic veins on the volume-rendering images of 3D-MDCTA was evaluated using a 5-point grade. Dunnett's test was used to compare the mean enhancement value and mean grades of image quality (700 mgI/kg dose group was control).

Results

The mean enhancement values of portal and hepatic vein in the group with 500 and 600 mgI/kg were significantly lower than those of the control group. During visual assessment, a significantly lower mean grades were observed in 500 mgI/kg groups for the portal vein, and 500 and 600 mgI/kg groups for hepatic vein. There were no significant intergroup differences in mean enhancement values and visual assessment among the groups using 630 mgI/kg or more.

Conclusion

Iodine doses of 630 mgI/kg was recommended for 3D-MDCTA.     

64-slice computed tomography assessment of coronary artery stents: a phantom study

Purpose: To compare the use of a new 64-slice computed tomography (CT) scanner with 16-slice CT in the visualization of coronary artery stent lumen.

Material and Methods: Eight different coronary artery stents, each with a diameter of 3 mm, were placed in a static chest phantom. The phantom was positioned in the CT gantry at an angle of 0° and 45° towards the z-axis and examined with both a 64-slice and a 16-slice CT scanner. Effective slice thickness was 0.6 mm with 64-slice CT and 1 mm with 16-slice CT. A reconstruction increment of 0.3 mm was applied in both scanners. Image quality was assessed visually using a 5-point grading scale. Stent diameters were measured and compared using paired Wilcoxon tests.

Results: Artificial lumen reduction was significantly less with 64-slice than with 16-slice CT. Average visible stent lumen was 53.4% using 64-slice CT and 47.5% with 16-slice MSCT. Most severe artifacts were seen in stents with radiopaque markers. Using 64-slice CT, image noise increased by approximately 30% due to thinner slice thickness.

Conclusion: Improved spatial resolution of 64-slice CT resulted in superior assessment of coronary artery stent lumen compared to 16-slice CT. However, a relevant part of the stent lumen is still not assessable with multi-slice CT.     

Usefulness of saline pushing in reduction of contrast material dose in abdominal CT: evaluation of time-density curve for the aorta, portal vein and liver

The effects of saline pushing after contrast material injection were investigated as well as the possibility for this technique to reduce contrast material doses in liver CT examinations. 52 patients were divided randomly into three groups: 100 ml of contrast material (300 mg I ml(-1)) only (A; n = 19), 100 ml of contrast material pushed with 50 ml of saline solution (B; n = 17), and 85 ml of contrast material pushed with 50 ml of saline solution (C; n = 16). Single-level images were obtained at the level of the main portal vein after the initiation of contrast material injection. There were no significant differences in the mean peak enhancement values (PE) and the mean time to peak enhancement values (TPE) of the aorta between the three groups. The mean PE of the portal vein in group B increased 21 HU over that in group A (p<0.05), and there was no significant difference between groups A and C. The mean PE of the liver in group B increased 7 HU over that in group A (p<0.05), and there was no significant difference between groups A and C. The mean TPE of the portal vein was shorter by 4 s (p<0.05), and that of the liver was shorter by 5 s (p<0.05) in group C compared with those in group A. In conclusion, saline pushing increases the enhancement values of the portal vein and liver, and allows a contrast material dose reduction of 15 ml without decreasing hepatic and vascular enhancement at adequate scan timing.     

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.     

Is subcutaneous local anesthesia in shoulder magnetic resonance arthrography necessary?

Background: Magnetic resonance arthrography is a well-established diagnostic method in degenerative and traumatic disorders of the shoulder. Some radiologists prefer to apply a local anesthetic to the skin prior to performing the joint puncture. However, no information regarding the efficacy of local anesthetics exists.

Purpose: To assess patient discomfort in arthrography injection.

Material and Methods: A patient survey (n = 74) utilizing a visual analog scale (VAS) measured the intensity of pain in arthrography injection by those receiving local anesthetics (n = 36) versus those who did not (n = 38).

Results: Mean VAS scores were 20.8 (median 10.5, SD 24.3) for those receiving local anesthetics versus 19.3 (median 13.0, SD 20.7) for those who did not (P = 0.83, Mann-Whitney U test).

Conclusion: Routine use of local anesthesia of the skin in arthrography injection is unnecessary.     

Living related liver transplantation: preoperative magnetic resonance imaging for assessment of hepatic vasculature of donor candidates

Purpose: To evaluate the accuracy of magnetic resonance angiography (MRA) for preoperative assessment of hepatic vascular anatomy in liver donors before living related liver transplantation.

Material and Methods: A total of 55 consecutive living liver donors (mean age 42 years, range 18-68 years) underwent multiphase contrast-enhanced MRA of the hepatic vessels. Two readers categorized vessel visualization on a five-point scale and recorded vascular anatomy or variations thereof for the arterial, portal venous and venous systems. All 55 living liver donors subsequently underwent right hemihepatectomy for hemiliver donation, and preoperative MRA results were correlated with surgical findings.

Results: Overall vessel visualization assessment demonstrated good or very good ratings for the majority of patients. For hepatic arteries, the mean score was 4.4±0.8 (mean±standard deviation), and for the portal venous and venous systems it was 4.6±0.7 and 4.3±0.8, respectively. Among all 55 donors, 16 (29%) demonstrated accessory or replaced hepatic arteries, and seven (13%) and 20 (36%) donors had surgically relevant portal vein (trifurcation or early right posterolateral branching types) and hepatic vein variations, respectively. Correlation coefficients between MRA and surgery were 0.94, 1.00 and 0.91 for hepatic arteries, portal veins and hepatic veins, respectively.

Conclusion: In the preoperative evaluation before living related liver donation, contrast-enhanced MR angiography was a highly accurate, noninvasive tool for visualizing the hepatic vasculature and variations thereof in liver donor candidates.     

Adult sail sign: radiographic and computed tomographic features

Background: The sail sign is a well-known radiographic feature of the pediatric chest. This sign can be observed in an adult population as well, but for a different reason.

Purpose: To investigate the sail sign appearing in adult chest radiography.

Material and Methods: Based on two anecdotal adult cases in which frontal chest radiographs showed the sail sign, we prospectively screened radiographs of 10,238 patients to determine the incidence of the sail sign found in adults in their 40s or older. The cause of the sail sign was assessed using computed tomography (CT).

Results: The sail sign was revealed in 10 (seven males, three females; median age 60.6 years) of 10,238 patients. Of these 10 patients with a sail sign on frontal radiographs, eight underwent CT. The frontal radiographs of these 10 patients showed a concave superior margin toward the lung in nine patients, a concave inferior margin in five, and a double-lined inferior margin in three. Lateral radiographs disclosed a focal opacity over the minor fissure in five of six patients, which was either fuzzy (n = 4) or sharp (n = 1) in its upper margin, and was sometimes double lined in the inferior margin (n = 3). CT revealed the anterior mediastinal fat to be the cause of the radiographic sail sign, which stretched laterally from the mediastinum to insinuate into the minor fissure.

Conclusion: The incidence of sail sign on adult chest radiographs is about 0.1%. The sign is specific enough to eliminate the need for more sophisticated imaging.