Jan Baxa

Pulmonary imaging using dual-energy CT, a role of the assessment of iodine and air distribution.

AIM The aim of the study is to present the feasibility of using dual-energy CT and the evaluation of iodine and air distribution in differentiation of pathological conditions. MATERIAL AND METHOD We used the data of 50 CT examinations performed due to suspected pulmonary embolism with any pathological finding except consolidation of the parenchyma. The patients underwent CT angiography of the pulmonary arteries on a dual-source CT (DSCT), with the two tubes independently operated at 140 and 80 kV. By exploiting the dual-energy information, iodine distribution maps were obtained in addition to the conventional CT images which served as a marker of pulmonary perfusion. Minimum intensity projections (MinIP) were used as a marker of air content. RESULTS By comparing the iodine distribution maps and MinIP images, it was possible to differentiate between the following templates of lung parenchyma: A--normal iodine and air distribution; B--iodine content deficit with minimal or with no redistribution of air; C--reduced iodine content and increased content of air; D--deficit of iodine content and increased content of air; E--increased iodine content and normal content of air; F--increased iodine content and reduced content of air; G--reduced perfusion and reduced content of air. The type A (five cases) was typical for the pulmonary embolism with preserved normal conditions of perfusion and ventilation. Type B (18 cases) occurred in pulmonary embolism; type C was found in case of inflammation of small respiratory airways (five cases); emphysema was typical for type D (nine cases); increased perfusion was observed in the parenchyma preserved from emphysema or preserved from embolism in cases of emphysema or pulmonary embolism; type F occurred in pulmonary interstitial edema (four cases) both with pulmonary infection; finally type G was found in interstitial lung diseases (five cases). CONCLUSION Imaging of the pulmonary circulation by means of dual-energy CT opens the potential to study pathological changes of circulatory and pulmonary perfusion impairments, our presented work signs the important relations between iodine and air distribution which have to be thought in the interpretation of dual-energy perfusion imaging of the lungs.

Length of Occlusion Predicts Recanalization and Outcome After Intravenous Thrombolysis in Middle Cerebral Artery Stroke

Background and Purpose— The length of large vessel occlusion is considered a major factor for therapy in patients with ischemic stroke. We used 4D-CT angiography evaluation of middle cerebral artery occlusion in prediction of recanalization and favorable clinical outcome and after intravenous thrombolysis (IV-tPA). Methods— In 80 patients treated with IV-tPA for acute complete middle cerebral artery/M1 occlusion determined using CT angiography and temporal maximum intensity projection, calculated from 4D-CT angiography, the length of middle cerebral artery proximal stump, occlusion in M1 or M1 and M2 segment were measured. Univariate and multivariate analyses were performed to define independent predictors of successful recanalization after 24 hours and favorable outcome after 3 months. Results— The length of occlusion was measureable in all patients using temporal maximum intensity projection. Recanalization thrombolysis in myocardial infarction 2 to 3 was achieved in 37 individuals (46%). The extension to M2 segment as a category (odds ratio, 4.58; 95% confidence interval, 1.39–15.05; P=0.012) and the length of M1 segment occlusion (odds ratio, 0.82; 95% confidence interval, 0.73–0.92; P=0.0007) with an optimal cutoff value of 12 mm (sensitivity 0.67; specificity 0.71) were significant independent predictors of recanalization. Favorable outcome (modified Rankin scale 0–2) was achieved in 25 patients (31%), baseline National Institutes of Health Stroke Scale (odds ratio, 0.82; 95% confidence interval, 0.72–0.93; P=0.003) and the length of occlusion M1 in segment (odds ratio, 0.79; 95% confidence interval, 0.69–0.91; P=0.0008) with an optimal cutoff value of 11 mm (sensitivity 0.74; specificity 0.76) were significant independent predictors of favorable outcome. Conclusions— The length of middle cerebral artery occlusion is an independent predictor of successful IV-tPA treatment.

Aortic annulus and ascending aorta: Comparison of preoperative and periooperative measurement in patients with aortic stenosis

BACKGROUND Precise determination of the aortic annulus size constitutes an integral part of the preoperative evaluation prior to aortic valve replacement. It enables the estimation of the size of prosthesis to be implanted. Knowledge of the size of the ascending aorta is required in the preoperative analysis and monitoring of its dilation enables the precise timing of the operation. Our goal was to compare the precision of measurement of the aortic annulus and ascending aorta using magnetic resonance (MR), multidetector-row computed tomography (MDCT), transthoracic echocardiography (TTE), and transoesophageal echocardiography (TEE) in patients with degenerative aortic stenosis. METHODS AND RESULTS A total of 15 patients scheduled to have aortic valve replacement were enrolled into this prospective study. TTE was performed in all patients and was supplemented with TEE, CT and MR in the majority of patients. The values obtained were compared with perioperative measurements. For the measurement of aortic annulus, MR was found to be the most precise technique, followed by MDCT, TTE, and TEE. For the measurement of ascending aorta, MR again was found to be the most precise technique, followed by MDCT, TEE, and TTE. CONCLUSION In our study, magnetic resonance was found to be the most precise technique for the measurement of aortic annulus and ascending aorta in patients with severe degenerative aortic stenosis.

Dual-phase dual-energy CT in patients with lung cancer: assessment of the additional value of iodine quantification in lymph node therapy response

AbstractObjectivesTo investigate the potential contribution of iodine uptake calculation from dual-phase dual-energy CT (DE-CT) for lymph node staging and therapy response monitoring in lung cancer patients.MethodsRetrospective analysis of 27 patients with non-small cell lung carcinoma (NSCLC), who underwent dual-phase DE-CT before and after chemotherapy, was performed. Iodine uptake (mg/mL) and total iodine uptake (mg) were calculated using prototype software in the early (arterial) and late (venous) post-contrast circulatory phase in 110 mediastinal lymph nodes. The arterial enhancement fraction (AEF) was calculated and compared with lymph node size and response to chemotherapy.ResultsA significant difference of AEF was observed between enlarged (90.4 %; 32.3–238.5 %) and non-enlarged (72.7 %; −37.5-237.5 %) lymph nodes (p = 0.044) before treatment onset. A significantly different change of AEF in responding (decrease of 26.3 %; p = 0.022) and non-responding (increase of 43.0 %; p = 0.031) lymph nodes was demonstrated. A higher value of AEF before treatment was observed in lymph nodes with subsequent favourable response (88.6 % vs. 77.7 %; p = 0.122), but this difference did not reach statistical significance.ConclusionsThe dual-phase DE-CT examination with quantification of ratio of early and late post-contrast iodine uptake is a feasible and promising method for the functional evaluation of mediastinal lymph nodes including therapy response assessment.Key Points• Dual-phase DE-CT is beneficial for mediastinal lymph node assessment in NSCLC. • Arterial to venous iodine uptake ratio was higher in enlarged lymph nodes. • Change of arterial enhancement fraction correlated to therapy response.

Dual-Phase Dual-Energy CT in Patients Treated with Erlotinib for Advanced Non-Small Cell Lung Cancer: Possible Benefits of Iodine Quantification in Response Assessment.

AbstractObjectivesTo investigate the relationship of dual-phase dual-energy CT (DE-CT) and tumour size in the evaluation of the response to anti-EGFR therapy in patients with advanced non-small cell lung cancer (NSCLC).MethodsDual-phase DE-CT was performed in 31 patients with NSCLC before the onset of anti-EGFR (erlotinib) therapy and as follow-up (mean 8 weeks). Iodine uptake (IU; mg/mL) was quantified using prototype software in arterial and venous phases; arterial enhancement fraction (AEF) was calculated. The change of IU before and after therapy onset was compared with anatomical evaluation in maximal transverse diameter and volume (responders vs. non-responders).ResultsA significant decrease of IU in venous phase was proved in responders according to all anatomical parameters (p=0.002–0.016). In groups of non-responders, a significant change of IU was not proved with variable trends of development. The most significant change was observed using the anatomical parameter of volume (cut-off 73 %). A significant difference of percentage change in AEF was proved between responding and non-responders (p=0.019–0.043).ConclusionDual-phase DE-CT with iodine uptake quantification is a feasible method with potential benefit in advanced assessment of anti-EGFR therapy response. We demonstrated a decrease in vascularization in the responding primary tumours and non-significant variable development of vascularization in non-responding tumours.Key Points• Dual-phase DE-CT is feasible for vascularization assessment of NSCLC with anti-EGFR therapy. • There was a significant decrease of iodine uptake in responding tumours. • There was a non-significant and variable development in non-responding tumours. • There was significant difference of AEF percentage change between responders and non-responders.

Multidetector computed tomography of chest trauma: indications, technique and interpretation

BackgroundChest traumas are a significant cause of mortality and morbidity, especially in the younger population.MethodsDiagnostic imaging plays a key role in their management. Multidetector computed tomography (MDCT) is the most important imaging method in this field. Its advantages include especially high speed and high geometric resolution in any plane.ResultsThe method allows us to view large parts of the body with minimal motion artifacts and to create accurate multiplanar and three-dimensional (3D) reformations, which make the diagnosis significantly more accurate. Because of its advantages MDCT has become the first-choice method in high-energy traumas.ConclusionThis article summarises the position of MDCT in the diagnostic algorithm of chest injuries, technical aspects of the examination and imaging findings in traumas of the individual chest compartments.Teaching Points• Diagnostic imaging plays a key role in the management of high-energy chest trauma.• MDCT is the most important imaging method in this kind of injury, as detailed information can be acquired in a short acquisition time.• Multiplanar and three-dimensional (3D) reformattings make the diagnosis significantly more accurate.

Quantitative evaluation of the performance of a new test bolus-based computed tomographic angiography contrast-enhancement-prediction algorithm.

ObjectivesThe objective of this study was to assess the robustness of a novel test bolus (TB)–based computed tomographic angiography (CTA) contrast-enhancement–prediction (CEP) algorithm by retrospectively quantifying the systematic and random errors between the predicted and true enhancements. Materials and MethodsAll local institutional review boards approved this retrospective study, in which a total of 72 (3 × 24) anonymized cardiac CTA examinations were collected from 3 hospitals. All patients (46 men; median age, 62 years [range, 31–81 years]) underwent a TB scan and a cardiac CTA according to local scan and injection protocols. For each patient, a shorter TB signal and TB signals with lower temporal resolution were derived from the original TB signal. The CEP algorithm predicted the enhancement in the descending aorta (DAo) on the basis of the TB signals in the DAo, the injection protocols and kilovolt settings, as well as population-averaged blood circulation characteristics. The true enhancement was extracted with a region of interest along the DAo centerline. For each patient, the errors in timing and amplitude were calculated; differences between the hospitals were assessed using the 1-way analysis of variance (P < 0.05) and variations between the TB signals were assessed using the within-subject standard deviation. ResultsNo significant differences were found between the 3 hospitals for any of the TB signals. With errors in the amplitude and timing of 0.3% ± 15.6% and −0.2 ± 2.0 seconds, respectively, no clinically relevant systematic errors existed. Shorter- and coarser-time–sampled TB signals introduced a within-subject standard deviation of 4.0% and 0.5 seconds, respectively. ConclusionsThis TB-based CEP algorithm has no systematic errors in the timing and amplitude of predicted enhancements and is robust against coarser-time–sampled and incomplete TB scans.

Low contrast volume run-off CT angiography with optimized scan time based on double-level test bolus technique – feasibility study

PURPOSE To verify the technical feasibility of low contrast volume (40 mL) run-off CT angiography (run-off CTA) with the individual scan time optimization based on double-level test bolus technique. MATERIALS AND METHODS A prospective study of 92 consecutive patients who underwent run-off CTA performed with 40 mL of contrast medium (injection rate of 6 mL/s) and optimized scan times on a second generation of dual-source CT. Individual optimized scan times were calculated from aortopopliteal transit times obtained on the basis of double-level test bolus technique--the single injection of 10 mL test bolus and dynamic acquisitions in two levels (abdominal aorta and popliteal arteries). Intraluminal attenuation (HU) was measured in 6 levels (aorta, iliac, femoral and popliteal arteries, middle and distal lower-legs) and subjective quality (3-point score) was assessed. Relations of image quality, test bolus parameters and arterial circulation involvement were analyzed. RESULTS High mean attenuation (HU) values (468; 437; 442; 440; 342; 274) and quality score in all monitored levels was achieved. In 91 patients (0.99) the sufficient diagnostic quality (score 1-2) in aorta, iliac and femoral arteries was determined. A total of 6 patients (0.07) were not evaluable in distal lower-legs. Only the weak indirect correlation of image quality and test-bolus parameters was proved in iliac, femoral and popliteal levels (r values: -0.263, -0.298 and -0.254). The statistically significant difference of the test-bolus parameters and image quality was proved in patients with occlusive and aneurysmal disease. CONCLUSION We proved the technical feasibility and sufficient quality of run-off CTA with low volume of contrast medium and optimized scan time according to aortopopliteal transit time calculated from double-level test bolus.

Regadenoson-Stress Dynamic Myocardial Perfusion Improves Diagnostic Performance of CT Angiography in Assessment of Intermediate Coronary Artery Stenosis in Asymptomatic Patients.

The prospective study included 54 asymptomatic high-risk patients who underwent coronary CT angiography (CTA) and regadenoson-induced stress CT perfusion (rsCTP). Diagnostic accuracy of significant stenosis (≥50%) determination was evaluated for CTA alone and CTA + rsCTP in 27 patients referred to ICA due to the positive rsCTP findings. Combined evaluation of CTA + rsCTP had higher diagnostic accuracy over CTA alone (per-segment: specificity 96 versus 68%, p = 0.002; per-vessel: specificity 95 versus 75%, p = 0.012) and high overruling rate of rsCTP was proved in intermediate stenosis (40–70%). Results demonstrate a significant additional value of rsCTP in the assessment of intermediate coronary artery stenosis found with CTA.

Phlegmasia cerulea dolens as a complication of a severe form of acute hemorrhagic-necrotizing pancreatitis

Phlegmasia cerulea dolens is an extreme form of deep venous thrombosis with a proximal localization of the blockage, most frequently in the ileofemoral area. Symptoms are graded as follows: swelling of the entire extremity, pain, and cyanosis. This form of the disease is rare, occurring most frequently in the terminal stage of malignancies. Diagnosis of phlegmasia usually causes no problems because the proper diagnosis is usually revealed during clinical examination and confirmed by imaging techniques. The authors present a case report of phlegmasia cerulean dolens and discuss the options for treatment.