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Christoph Engelke

Publications and source records attributed to Christoph Engelke.

18 recordsLinked to original sources
PubMed2006

Computer-aided detection and automated CT volumetry of pulmonary nodules.

With use of multislice computed tomography (MSCT), small pulmonary nodules are being detected in vast numbers, constituting the majority of all noncalcified lung nodules. Although the prevalence of lung cancers among such lesions in lung cancer screening populations is low, their isolation may contribute to increased patient survival. Computer-aided diagnosis (CAD) has emerged as a diverse set of diagnostic tools to handle the large number of images in MSCT datasets and most importantly, includes automated detection and volumetry of pulmonary nodules. Current CAD systems can significantly enhance experienced radiologists' performance and outweigh human limitations in identifying small lesions and manually measuring their diameters, augment observer consistency in the interpretation of such examinations and may thus help to detect significantly higher rates of early malignomas and give more precise estimates on chemotherapy response than can radiologists alone. In this review, we give an overview of current CAD in lung nodule detection and volumetry and discuss their relative merits and limitations.

Adult↗
PubMed2006

Pulmonary embolism at multi-detector row CT of chest: one-year survival of treated and untreated patients.

PURPOSE: To retrospectively assess outcome in patients with clinically unsuspected pulmonary embolism (PE) at chest multi-detector row computed tomography (CT). MATERIALS AND METHODS: Institutional review board approval and informed consent were not required. PE was assessed in consecutive CT scans in 1966 patients (mean age, 60 years; range, 15-96 years; male-female ratio, 1.79) and graded with severity score. Studies with true-positive and false-negative radiologic diagnoses were determined. Coexisting morbidity, anticoagulant therapy (ACT), complications, and 1-year outcome were reviewed. Statistical evaluation included Mann-Whitney U test, chi(2) test, Poisson regression, and Kaplan-Meier statistics. RESULTS: Scans were PE positive in 117 patients. Clinical data review was complete in 96 patients; 63 of 96 patients had malignancy; in 58, PE was not suspected. In 38 of these 58 patients, radiology report findings were false-negative (mean severity score, 20.21 +/- 17.88 [standard deviation] and 9.55 +/- 7.12 for those with true-positive and false-negative findings, respectively; P = .012). Forty-nine patients received therapeutic ACT; 21, prophylactic ACT; and 26, no treatment. PE severity was higher in patients with therapeutic ACT versus those without (P < .001). Bleeding complications were more frequent with therapeutic ACT (two early deaths, five major nonfatal hemorrhages) than without (one minor hemorrhage; P = .037). There were eight early deaths (therapeutic ACT, seven; without ACT, one; P = .037). Positive predictors of early death included severity score >28, use of systemic thrombolytic therapy, occurrence of major hemorrhage, and new-onset cardiac or renal failure (P = .001-.043). Negative predictors were report with false-negative findings and no therapeutic ACT (P = .007-.037). Predictors of late death (n = 25) were older age, malignancy, and renal failure (P = .001-.043). CONCLUSION: Clinically unsuspected PE may remain undetected at routine chest CT; these patients have favorable short-term outcome without therapeutic ACT.

Adolescent↗
PubMed2006

Acute pulmonary embolism on MDCT of the chest: prediction of cor pulmonale and short-term patient survival from morphologic embolus burden.

OBJECTIVE: To predict cor pulmonale and short-term outcome in patients with pulmonary embolism (PE), we retrospectively investigated three morphology-based MDCT systems for scoring pulmonary artery obstruction. MATERIALS AND METHODS: Eighty-nine consecutive patients (51 men and 38 women; age range, 23-83 years; median, 63.3 years) with an MDCT diagnosis of acute PE were included in the study. Sixty-four patients had a coexisting malignancy. PE severity was assessed by two masked observers using three percentage arterial obstruction indexes: two severity scores adapted from conventional angiography (excluding and including arterial branch obstruction grading: scores A and B, respectively) and a CT-derived severity score (index C). Echocardiographic reports were reviewed for elevation of right ventricular pressure. Obstruction index results were analyzed for correlation with pulmonary artery pressures and for prediction of cor pulmonale and 30-day survival. Statistical analysis included kappa, analysis of variance, linear correlation, chi-square, and logistic regression tests. RESULTS: Kappa values of 0.89, 0.82, and 0.78 were obtained for interobserver agreement on PE severity for indexes A, B, and C, respectively. PE severity was moderate but varied significantly between the scores (for index A: median, 25.0%; range, 6.3-100; for index B: median, 12.5%; range, 3.1-65.6; for index C: median, 7.1%; range, 0.65-65.8; p < 0.0001 [analysis of variance]). Index C correlated best with pulmonary artery pressures (r = 0.69; p < 0.0016) and the presence of cor pulmonale (p = 0.0051; odds ratio [OR], 1.20/percentage increase [95% confidence interval, 1.05-1.35]; for an index C cutoff of 21.3%: p = 0.0001; positive predictive value, 1; negative predictive value, 0.87). Eight patients died within 30 days after CT. The PE severity of indexes A and B was not associated with patient outcome (p > 0.05). With score C, PE severity was a significant predictor of early death (p = 0.018; OR, 1.03/percentage increase [95% confidence interval, 1.00-1.06]; for an index C cutoff of 21.3%: p = 0.018; overall OR, 6.77; positive predictive value, 0.24; negative predictive value, 0.96). CONCLUSION: Mastora score was a significant predictor of cor pulmonale and short-term outcome and may therefore allow therapy and risk stratification in patients with acute PE.

Acute Disease↗
PubMed2005

Inadequacy of manual measurements compared to automated CT volumetry in assessment of treatment response of pulmonary metastases using RECIST criteria.

The purpose of this study was to compare relative values of manual unidimensional measurements (MD) and automated volumetry (AV) for longitudinal treatment response assessment in patients with pulmonary metastases. Fifty consecutive patients with pulmonary metastases and repeat chest multidetector-row CT (median interval=2 months) were independently assessed by two radiologists for treatment response using Response Evaluation Criteria In Solid Tumours (RECIST). Statistics included relative measurement errors (RME), intra-/interobserver correlations, limits of agreement (95% LoA), and kappa. A total of 202 metastases (median volume=182.22 mm(3); range=3.16-5,195.13 mm(3)) were evaluated. RMEs were significantly higher for MD than for AV (intraobserver RME=2.34-3.73% and 0.15-0.22% for MD and AV respectively; P<0.05. Interobserver RME=3.53-3.76% and 0.22-0.29% for MD and AV respectively; P<0.05). Overall correlation was significantly better for AV than for MD (P<0.05). Intraobserver 95% LoAs were -1.85 to 1.75 mm for MD and -11.28 to 9.84 mm(3) for AV. The interobserver 95% LoA were -1.46 to 1.92 mm for MD and -11.17 to 9.33 mm(3) for AV. There was total intra-/interobserver agreement on response using AV (kappa=1). MD intra- and interobserver agreements were 0.73-0.84 and 0.77-0.80 respectively. Of the 200 MD response ratings, 28 (14/50 patients) were discordant. Agreement using MD dropped significantly from total remission to progressive disease (P<0.05). We therefore conclude that AV allows for better reproducibility of response evaluation in pulmonary metastases and should be preferred to MD in these patients.

Adult↗
PubMed2005

Chest radiography with a digital flat-panel detector: experimental receiver operating characteristic analysis.

PURPOSE: To evaluate the influence of different detector radiation doses and peak kilovoltage settings on diagnostic performance and radiation dose at posteroanterior (PA) chest radiography performed with an amorphous silicon flat-panel detector (FPD). MATERIALS AND METHODS: All examinations were performed by using a digital FPD. PA chest radiographs of an anthropomorphic chest phantom were obtained with detector radiation doses of 2.50 microGy (system speed, 400), 1.56 microGy (speed, 640), and 1.25 microGy (speed, 800) and with peak kilovoltage values of 100, 120, and 140 kVp. Four types of simulated lesions-nodules of different sizes, polylobulated lesions, interstitial-nodular lesions, and interstitial-reticular lesions-were superimposed on the phantom. After four radiologists assessed all of the images, receiver operating characteristics analysis was performed. In addition, the entrance surface dose was measured and the effective dose was calculated. RESULTS: Reduced detector dose led to significantly decreased diagnostic performance in overall lesion detection (P <.05). However, over pulmonary areas only, this effect could not be seen. With use of the same kilovoltage values, reducing the detector dose, even to 1.25 microGy (speed, 800), did not lead to significantly decreased lesion detectability. In terms of diagnostic performance and effective dose, 120 kVp was the most effective. CONCLUSION: Standard PA chest radiographs should still be acquired at a detector dose of 2.50 microGy (speed, 400) with 120 kVp to yield the highest diagnostic performance. However, when the present analysis was focused on the lung fields only, no significant loss in diagnostic performance could be demonstrated, even after a 50% reduction in radiation dose.

Observer Variation↗
PubMed2004

Computer-assisted detection of pulmonary nodules: evaluation of diagnostic performance using an expert knowledge-based detection system with variable reconstruction slice thickness settings.

The purpose of this study was to evaluate the performance of a computer-assisted diagnostic (CAD) tool using various reconstruction slice thicknesses (RST). Image data of 20 patients undergoing multislice CT for pulmonary metastasis were reconstructed at 4.0, 2.0 and 0.75 mm RST and assessed by two blinded radiologists (R1 and R2) and CAD. Data were compared against an independent reference standard. Nodule subgroups (diameter >10, 4-10, <4 mm) were assessed separately. Statistical methods were the ROC analysis and Mann-Whitney U test. CAD was outperformed by readers at 4.0 mm (Az = 0.18, 0.62 and 0.69 for CAD, R1 and R2, respectively; P<0.05), comparable at 2.0 mm (Az = 0.57, 0.70 and 0.69 for CAD, R1 and R2, respectively), and superior using 0.75 mm RST (Az = 0.80, 0.70 and 0.70 and sensitivity = 0.74, 0.53 and 0.53 for CAD, R1 and R2, respectively; P<0.05). Reader performances were significantly enhanced by CAD (Az = 0.93 and 0.95 for R1 + CAD and R2 + CAD, respectively, P<0.05). The CAD advantage was best for nodules <10 mm (detection rates = 93.3, 89.9, 47.9 and 47.9% for R1 + CAD, R2 + CAD, R1 and R2, respectively). CAD using 0.75 mm RST outperformed radiologists in nodules below 10 mm in diameter and should be used to replace a second radiologist. CAD is not recommended for 4.0 mm RST.

Adult↗
PubMed2004

Computer-assisted detection of pulmonary nodules: performance evaluation of an expert knowledge-based detection system in consensus reading with experienced and inexperienced chest radiologists.

To evaluate the performance of experienced versus inexperienced radiologists in comparison and in consensus with an interactive computer-aided detection (CAD) system for detection of pulmonary nodules. Eighteen consecutive patients (mean age: 62.2 years; range 29-83 years) prospectively underwent routine 16-row multislice computed tomography (MSCT). Four blinded radiologists (experienced: readers 1, 2; inexperienced: readers 3, 4) assessed image data against CAD for pulmonary nodules. Thereafter, consensus readings of readers 1+3, reader 1+CAD and reader 3+CAD were performed. Data were compared against an independent gold standard. Statistical tests used to calculate interobserver agreement, reader performance and nodule size were Kappa, ROC and Mann-Whitney U. CAD and experienced readers outperformed inexperienced readers (Az=0.72, 0.71, 0.73, 0.49 and 0.50 for CAD, readers 1-4, respectively; P<0.05). Performance of reader 1+CAD was superior to single reader and reader 1+3 performances (Az=0.93, 0.72 for reader 1+CAD and reader 1+3 consensus, respectively, P<0.05). Reader 3+CAD did not perform superiorly to experienced readers or CAD (Az=0.79 for reader 3+CAD; P>0.05). Consensus of reader 1+CAD significantly outperformed all other readings, demonstrating a benefit in using CAD as an inexperienced reader replacement. It is questionable whether inexperienced readers can be regarded as adequate for interpretation of pulmonary nodules in consensus with CAD, replacing an experienced radiologist.

Adult↗
PubMed2004

Flat panel detector-based volumetric CT: prototype evaluation with volumetry of small artificial nodules in a pulmonary phantom.

PURPOSE: To evaluate amorphous silicone-based flat panel detector volumetric CT (VCT) in volumetric assessment of small nodules in a pulmonary phantom, and to perform comparative experiments with 4-row multislice CT (MSCT). MATERIALS AND METHODS: Seventy synthetic nodules (volume range (VR): 0.99-185.77 mm; estimated diameter range (ED): 1.4-7.8 mm) were scanned in spherical shape and after iso-volumetric deformation with VCT and MSCT using 0.63 mm (MSCT I) and 1.25 mm (MSCT II) collimations. Measured volumes and percent measurement errors (PME) were compared between the 3 CT modes before and after nodule deformation. For each measurement pair before and after deformation, the post-deformation relative volumetric inaccuracy (RIA) was determined. Volume, PME, and RIA differences were tested using Wilcoxon and Friedman methods. RESULTS: The volumes of the smallest nodules (VR = 0.99-2.83 mm, ED = 1.4-1.9 mm) were computable only from VCT scans. In VCT, measured volumes and PMEs before and after deformation differed significantly less compared with MSCT (VCT: P = 0.06 and 0.56, respectively; MSCT I: P = 0.0012 and 0.006, respectively; and MSCT II: P < 0.0001 for measured volumes and PMEs). In VCT PMEs of 5.51-32.21 mm nodules (ED = 2.4-4.1 mm) before and after deformation were significantly below MSCT (VCT averages = 1.43-1.91% and 1.98-3.48%, for spherical and deformed nodules, respectively; MSCT I averages = 9.97-26.1% and 12.16-38.10%, respectively; MSCT II averages = 17.79-46.18 and 18.14-54.66%, respectively, P < 0.0001) and RIAs in VCT were significantly below MSCT (VCT: 0.50-2.62%, MSCT I: 3.35-15.97%, and MSCT II: 4.29-18.46%; P = 0.0001-0.0039). CONCLUSION: VCT volumetry is highly accurate in volumetry of smallest nodules with estimated diameters of 1.4-4.1 mm.

Humans↗
PubMed2002

Peripheral aneurysm rupture in a patient with inactive systemic lupus erythematosus.

We describe a patient with inactive systemic lupus erythematosus (SLE) presenting with sudden haemothorax, due to a ruptured internal mammary artery (IMA) aneurysm 7 years after the corticosteroid treatment was terminated. The unusual imaging findings and the treatment with embolization are discussed with a view to the role of a regular vascular screening in this patient group.

Aneurysm, Ruptured↗
PubMed2002

Autologous thrombin for treatment of pseudoaneurysms.

Femoral pseudoaneurysms arise in up to 2% of patients after femoral cannulation for cardiac catheterisation. We used autologous thrombin for percutaneous obliteration of pseudoaneurysms occurring after catheterisation. We prepared autologous thrombin isolates from blood of ten patients with femoral pseudoaneurysms, and injected this solution into the pseudoaneurysms with duplex imaging guidance. We then assayed thrombin activity. All pseudoaneurysms were successfully thrombosed without substantial complications, although three patients needed a repeat procedure within 24 h. We have shown that autologous thrombin-induced thrombosis of pseudoaneurysms is reliable, simple, safe, and cheaper than commercial bovine or human thrombin, and avoids risks of anaphylaxis and contamination with prions.

Aneurysm, False↗
PubMed2002

Endovascular repair of thoracic aortic aneurysm and intramural hematoma in giant cell arteritis.

An 80-year-old woman with established giant cell arteritis presented at the authors' institution with a 6.5-cm false aneurysm of the descending thoracic aorta complicated by focal dissection and intramural hematoma after a 1-week history of acute-onset chest pain. The patient underwent uncomplicated endovascular aortic repair with a 32-mm x 15-cm TagExcluder stent-graft. After the procedure, the intramural hematoma resolved and the patient's corticosteroid and immunosuppressive therapy was repeatedly adjusted. However, the giant cell arteritis activity relapsed after 8 months with development of a similar 1.5-cm false aneurysm below the thoracic stent-graft, complicated by focal intramural hematoma. Repeat uncomplicated thoracic stent-graft implantation was performed and CT follow-up displayed resorption of the intramural hematomas with no evidence of endoleak or any new aortic pathology. This report discusses the difficult management of patients with relapsing active aortic giant cell arteritis and the potential role for endovascular thoracic aortic repair.

Aged↗
PubMed2002

Cutting balloon angioplasty for resistant renal artery in-stent restenosis.

A 76-year-old woman presented with recurrent arterial hypertension 6 months after uncomplicated primary renal artery stent placement. Diagnostic arteriography revealed severe renal artery in-stent restenosis. On repeat intervention, the lesion was resistant to attempted conventional percutaneous transluminal angioplasty (PTA) with unchanged systolic pressure gradients across the stent. Cutting balloon angioplasty (CBA) was performed with use of a 4-mm cutting balloon (IVT, San Diego, CA). CBA successfully reduced the pressure gradient to below the level of significance. Subsequent conventional PTA enhanced the lumen diameter inside the stent. The arterial hypertension reverted to normal values and duplex ultrasonography (US) at 10-month follow-up demonstrated normal renal artery hemodynamics without stenosis. CBA for potential use in renal artery in-stent restenosis and other peripheral neointimal hyperplasia is discussed.

Aged↗
PubMed2002

Internal iliac artery embolization with bilateral occlusion before endovascular aortoiliac aneurysm repair-clinical outcome of simultaneous and sequential intervention.

PURPOSE: To retrospectively evaluate the clinical outcome of patients after simultaneous or sequential internal iliac artery (IIA) embolization for bilateral IIA occlusion. MATERIALS AND METHODS: Sixteen patients (65-88 y; mean, 75.6 y; two women), 11 with aortobiiliac aneurysms, three with bilateral common iliac artery (CIA)/IIA aneurysms, and two with unilateral CIA/IIA aneurysms, underwent IIA occlusion before endovascular aortoiliac repair. Eight patients underwent simultaneous bilateral IIA embolization before endovascular aortic repair (EVAR). Eight patients had sequential bilateral IIA occlusion. The outcome was assessed by clinical follow-up. RESULTS: There were no severe ischemic complications such as buttock necrosis or acute bowel, bladder, or spinal cord ischemia. Early ischemic complications occurred in 25% (buttock/thigh claudication, n = 3, 18.8%; and sexual dysfunction, n = 1, 6.2%) and had an onset not later than 6 months after intervention: buttock claudication resolved (n = 2) or persisted after aggravation by inferior mesenteric artery embolization for type II endoleak (n = 1). Impotence in a fourth patient persisted. The ischemic complication rate after 6 months was 30% (three of 10) because of a fifth patient who developed ischemic colitis with aggravation of ischemic heart disease after 15 months. The mean follow-up duration was 19.7 months. Patients with simultaneous embolization had a lower complication rate than those with sequential embolization (one of eight [12.5%] vs four of eight [50%], respectively). CONCLUSIONS: IIA embolization for bilateral IIA occlusion can be performed with a complication rate comparable with results of previous studies of unilateral IIA embolization. Chronic buttock claudication may be aggravated by embolization of aortic side branches. Late complications can have an insidious course and be initiated by low-output cardiac failure. Bilateral IIA occlusion is recommended only in patients who are considered unfit for aortic surgery.

Aged↗
PubMed2002

Cutting balloon percutaneous transluminal angioplasty for salvage of lower limb arterial bypass grafts: feasibility.

PURPOSE: To evaluate the feasibility of cutting balloon percutaneous transluminal angioplasty (PTA) for treatment of neointimal hyperplasia in peripheral arterial bypass grafts. MATERIALS AND METHODS: Fifteen consecutive patients (six women, nine men; age range, 57-89 years; mean age, 71 years) were treated with cutting balloon PTA for 16 anastomotic stenoses after infrainguinal bypass (prosthetic grafts, seven patients; prosthetic-vein composite grafts, two; venous grafts, five; and ileofemoral stent-graft, one). Cutting balloon PTA was followed by conventional PTA to improve anastomotic diameter. Patients with stenotic vein grafts underwent cutting balloon PTA after failed conventional PTA; the other patients were treated primarily with cutting balloon PTA. Criteria for success were a lumen diameter improvement of greater than 50% or residual stenosis of 20% or less. Follow-up was performed with color duplex ultrasonographic surveillance. Patency rates and durations were calculated with Kaplan-Meier survival curves and log-rank statistics. RESULTS: Attempted conventional PTA (n = 6) prior to cutting balloon PTA was unsuccessful. Cutting balloon PTA was technically successful in 15 (94%) of 16 lesions, without clinical complications. Two local restenoses and one graft occlusion occurred between 5 and 7 months. The cumulative 6-month primary and secondary graft patency rates were 84% and 92%, respectively. At 12 and 18 months, they were 67% (95% CI: 0.34, 0.86) and 83% (95% CI: 0.48, 0.96), respectively; mean follow-up was 10.0 months. CONCLUSION: Cutting balloon PTA proved feasible for treatment of resistant peripheral arterial bypass graft stenosis, commonly caused by neointimal hyperplasia, with excellent technical success. Short-term patency with this technique appears to be superior to that with conventional PTA, and it compares well with patency of atherectomy for salvage of infrainguinal bypass grafts.

Aged↗
PubMed2002

Autologous thrombin: a new embolization treatment for traumatic intrasplenic pseudoaneurysm.

PURPOSE: To report the use of autologous thrombin for transcatheter embolization of a traumatic parenchymal splenic pseudoaneurysm. CASE REPORT: A 15-year-old boy presented with a splenic parenchymal laceration after blunt abdominal trauma. The patient was managed conservatively but developed an intrasplenic pseudoaneurysm (grade III AAST scale) with subcapsular contrast extravasation after 3 weeks. Autologous thrombin was isolated from the patient's blood and subsequently delivered to the lesion by transcatheter superselective injection into the aneurysm neck. The patient was asymptomatic after the procedure. Nine months' follow-up demonstrated a normal spleen with completely homogenous parenchyma. CONCLUSIONS: Autologous thrombin injection to induce thrombosis of intrasplenic pseudoaneurysm represents a new treatment option for traumatic abdominal organ injuries. Intrasac thrombosis can be safely induced to successfully restore the splenic parenchymal integrity without introduction of foreign material and associated risks of adverse reactions or infection that might accompany the use of commercial thrombin preparations.

Adolescent↗
PubMed2002

Using 6-mm Cutting Balloon angioplasty in patients with resistant peripheral artery stenosis: preliminary results.

OBJECTIVE: The objective of this study was to assess the efficacy of 6-mm Cutting Balloon angioplasty in patients with resistant peripheral stenoses caused by neointimal hyperplasia or irradiation-induced arteriopathy in vascular territories that are not amenable for use of the smaller Cutting Balloons that are used in cardiology. CONCLUSION: Peripheral Cutting Balloon angioplasty with the new 6-mm Cutting Balloon device proved useful in the short term for treatment of peripheral arterial stenoses resistant to conventional angioplasty.

Adult↗
PubMedDate not supplied

High-resolution CT and CT angiography of peripheral pulmonary vascular disorders.

Peripheral pulmonary vascular disorders that can be evaluated with computed tomography (CT) include various disease entities with overlapping imaging features and a wide range of clinical manifestations. The overall accuracy of CT in the diagnosis of pulmonary vascular disorders increases with improved spatial resolution, administration of a high-flow contrast material bolus, and the use of cardiac gating. The integration of high-resolution CT and CT angiographic techniques into one scanning protocol has important clinical implications for multisection CT and makes it the imaging modality of choice in the evaluation of this complex group of disorders.

Angiography↗