Accuracy of Coronary Plaque Detection and Assessment of Interobserver Agreement for Plaque Quantification Using Automatic Coronary Plaque Analysis Software on Coronary CT Angiography.

PURPOSE: To evaluate the accuracy of automatic plaque detection and the interobserver agreement of automatic versus manually adjusted quantification of coronary plaques on coronary CT angiography (cCTA) using commercially available software. MATERIALS AND METHODS: 10 cCTA datasets were evaluated using plaque software. First, the automatically detected plaques were verified. Second, two observers independently performed plaque quantification without revising the automatically constructed plaque contours (automatic approach). Then, each observer adjusted the plaque contours according to plaque delineation (adjusted approach). The interobserver agreement of both approaches was analyzed. RESULTS: 32 of 114 automatically identified findings were true-positive plaques, while 82 (72 %) were false-positive. 20 of 52 plaques (38 %) were missed by the software (false-negative). The automatic approach provided good interobserver agreement with relative differences of 0.9 ±â€Š16.0 % for plaque area and -3.3 ±â€Š33.8 % for plaque volume. Both observers independently adjusted all contours because they did not represent the plaque delineation. Interobserver agreement decreased for the adjusted approach with relative differences of 25.0 ±â€Š24.8 % for plaque area and 20.0 ±â€Š40.4 % for plaque volume. CONCLUSION: The automatic plaque analysis software is of limited value due to high numbers of false-positive and false-negative plaque findings. The automatic approach was reproducible but it necessitated adjustment of all constructed plaque contours resulting in deterioration of the interobserver agreement. KEY POINTS: • Automatic plaque detection is limited due to high false-positive and false-negative findings.• Automatic plaque quantification was reproducible in the few accurately detected plaques.• The automatically constructed contours did not represent the plaque delineation.• Both observers independently adjusted the plaque contours.• Manual adjustment of plaque contours reduced the interobserver agreement. Citation Format: • Laqmani A, Klink T, Quitzke M et al. Accuracy of Coronary Plaque Detection and Assessment of Interobserver Agreement for Plaque Quantification Using Automatic Coronary Plaque Analysis Software on Coronary CT Angiography. Fortschr Röntgenstr 2016; 188: 933 - 939.

Comparison of Cine-MRI and Transthoracic Echocardiography for the Assessment of Aortic Root Diameters in Patients with Suspected Marfan Syndrome.

PURPOSE: Patients with Marfan syndrome require repeated imaging for monitoring of aortic root aneurysms. Therefore, we evaluated the agreement and reproducibility of cine-MRI and echocardiography measurements of the sinuses of Valsalva in patients with suspected Marfan syndrome. MATERIALS AND METHODS: 51 consecutive patients with suspected Marfan syndrome were prospectively examined using cine-MRI and echocardiography. Two readers independently measured aortic root diameters at the level of the sinuses of Valsalva in both cine-MRI and echocardiography. Statistics included intraclass correlation coefficient, Pearson correlation coefficient, Bland-Altman analysis, and two-sided t-test. RESULTS: In 38 of the 51 individuals (74.5 %), the diagnosis of Marfan syndrome was established according to the criteria of the Ghent-2 nosology. Cine-MRI measurements of the sinuses of Valsalva revealed a strong correlation with echocardiography (r = 0.929), but a statistically significant bias of -1.0  mm (p < 0.001). The mean absolute diameter for sinuses of Valsalva obtained by cine-MRI was 32.3  ±  5.8 mm as compared to 33.4  ±  5.4 mm obtained by echocardiography. Interobserver agreement of measurements of the sinuses of Valsalva was higher for cine-MRI than for echocardiography (p = 0.029). CONCLUSION: Despite small, but statistically significant differences in terms of agreement and reproducibility, cine-MRI and echocardiographic measurements of aortic root diameters provide comparable results without a significant clinical difference. Therefore both techniques may be used for monitoring of the aortic root in patients with Marfan syndrome.

Assessment of left ventricular function parameters with a new three-dimensional shape model.

PURPOSE: To evaluate a 3D model of the left ventricle (LV) which allows calculation of LV function parameters on the basis of both short axis (SA) and long axis (LA) cine acquisitions. Comparison with the conventional Simpson's rule method in a volunteer and patient collective. MATERIALS AND METHODS: Cine imaging was performed with a prospectively triggered SSFP sequence: trueFISP: TR 3.6 msec, TE 1.8 msec, bFFE: TR 3.0 msec, TE 1.4 msec, flip angle 60 degrees , resolution 1.37 x 1.37 mm, slice thickness 8 mm, gap 2 mm in SA orientation from apex to basis and in radial LA orientation (spacing 15 degrees) in 11 volunteers and 27 patients with mitral valve insufficiency. Five different volume computations were compared: Simpson's rule based on all SA slices (M0), 3D shape model based on all SA slices (M1a), 3D shape model based on 3 SA slices (M1b), 3D shape model based on all SA and LA slices (M2a), and 3D shape model based on 3 SA slices and 1 LA slice (M2b). RESULTS: M 0 and M 1a give similar results (r: 0.99, b: 0.98). M 2a produces larger volumes than M 0 (b: 0.85) due to the inclusion of the LA contours. M 1b effectively reproduces the volumes computed with M 0 (r: 0.99, b: 1.02). M 2b effectively reproduces the volumes computed with M 2a (r: 0.99, b: 0.94). M 2b and M 0 give similar results in the patient collective (r: 0.99, b: 0.97). CONCLUSION: The proposed 3D shape model allows merging of information acquired in different orientations and thus the combination of SA and LA contours with better coverage of the left ventricle. It provides a suitable fit with a reduced number of segmented contours.

Assessment of myocardial viability in ischemic heart disease by cardiac magnetic resonance imaging.

Assessment of myocardial viability aims at differentiating between viable and non-viable myocardium. The proof of dysfunctional but viable myocardium is crucial to predict outcome of revascularization after acute (AMI) and chronic myocardial infarction (CMI). Cardiac magnetic resonance imaging (CMRI) offers different options to detect viable myocardium: Measurements of end-diastolic wall thickness by cine-CMRI can be used to depict chronically scarred myocardium, but fails to detect acute myocardial necrosis. Low-dose dobutamine stimulation (LDDS) cine-CMRI analyses the contractile reserve of dysfunctional but viable myocardium under pharmacologic stimulus to identify viable myocardium in AMI and CMI with high specificity. Sensitivity of LDDS cine-CMRI is superior to LDDS echocardiography but reduced in patients with severely impaired left ventricular (LV) function. The delayed-enhancement (DE) technique directly visualises non-viable myocardium due to an altered contrast-media distribution in necrotic and fibrotic tissue. DE-CMRI identifies non-viable myocardium with high spatial resolution independently from LV function. The transmural extent of contrast enhancement in DE-CMRI is used to predict functional recovery after revascularization in AMI and CMI. Furthermore, the amount and pattern of contrast enhancement in DE-CMRI provide important prognostic information in both entities. Recent studies demonstrated the superiority of DE-CMRI compared to single photon emission tomography (SPECT) and positron emission tomography (PET) to assess myocardial viability. Therefore, DE-CMRI is currently recognised as the standard of reference for assessment of myocardial viability. The technical background, clinical application and accuracy of the different CMRI techniques to assess myocardial viability in AMI and CMI are discussed in this work.

Assessment of functional anatomy of the mitral valve in patients with mitral regurgitation with cine magnetic resonance imaging: comparison with transesophageal echocardiography and surgical results.

The ability of magnetic resonance imaging (MRI) to accurately define the functional anatomy of mitral regurgitation was assessed. Transesophageal echocardiography (TEE) and cine MRI were performed on 43 patients with mitral regurgitation and were compared for the jet number, location, direction and presence of a prolapse (atrial displacement, malapposition or a flail). In 36 patients, diagnostic accuracy in reference to surgery was assessed. Comparing TEE and MRI the jet number and location were judged in concordance in 86% of patients. Jet location did not show a significant difference (Wilcoxon: P = 0.66) and both modalities correlated strongly (Spearman: r = 0.68, P<0.0001). Jet direction was judged with high concordance (kappa=0.63). Additionally, prolapse evaluation showed high concordance (kappa: valve, 0.63; anterior mitral leaflet, 0.70; posterior mitral leaflet, 0.73). Compared with surgery, the sensitivity for the detection of malapposition of any leaflet or one of both leaflets ranged between 75% and 93% for TEE and 71% and 89% for MRI. Specificities ranged between 88 and 96% for TEE and 88 and 100% for MRI. TEE detected torn chordae in all ten patients, six of which were missed by MRI. MRI is comparable with TEE in prolapse and jet evaluation. MRI is inferior to TEE in depicting anatomical details such as torn chordae.

Assessment of nicorandil therapy in ischemic myocardial injury by using contrast-enhanced and functional MR imaging.

PURPOSE: To determine the potential of mesoporphyrin- and gadopentetate dimeglumine-enhanced and functional magnetic resonance (MR) imaging in the assessment of the acute effect of nicorandil on ischemic injury of the myocardium. MATERIALS AND METHODS: Spin-echo MR imaging was used to monitor changes in myocardial contrast and function in reperfused myocardial injury. Inversion-recovery echo-planar MR imaging was used to depict the injured region. Myocardial injury in rats was produced by using 30 minutes of coronary occlusion followed by 24 hours reperfusion. Nicorandil (n = 9) was infused during occlusion and early reperfusion. Control animals (n = 11) received no therapy. At 24 hours, after administration of mesoporphyrin and gadopentetate dimeglumine and histochemical staining, the function and size of the injured region of the left ventricle (LV) were determined. A t test was used to compare data between groups of animals, whereas regression and Bland-Altman analyses were used to determine correlation and agreement between MR imaging and histomorphometry, respectively. RESULTS: Treated animals showed reduced infarction size as compared with the control group from 25.6% +/- 7.9 (SD) to 7.9% +/- 6.8 of LV myocardial area (P < .001), as defined with mesoporphyrin-enhanced MR imaging; while the size of the rim increased from 10.8% +/- 10.0 to 16.1% +/- 14.4 (P < .05). The diastolic-midventricular cavity area was smaller in treated animals (15.2 mm(2) +/- 4.3) compared with the control group (28.5 mm(2) +/- 7.9; P < .001). At functional MR imaging, nicorandil improved systolic reduction in LV cavity area (57.5% +/- 17.3) compared with the control group (38.0% +/- 16.0; P < .05) and preserved regional LV wall thickening at the site of injury (12.2% +/- 11.1 in treated group vs 0.3% +/- 8.6 in the control group; P < .05). CONCLUSION: Contrast material-enhanced MR imaging has the potential to demonstrate reduction in size of ischemically injured myocardium, whereas functional MR imaging demonstrated the recovery of LV function 24 hours after nicorandil therapy.

Myocardial viability: magnetic resonance assessment of functional reserve and tissue characterization.

The determination of myocardial viability is crucial in patients with left ventricular dysfunction resulting from acute myocardial ischemia or chronic coronary artery disease. Viable myocardium will most likely benefit from revascularization procedures. However, the revascularization of scar tissue will not lead to improvement of ventricularfunction andfurthermore bears unnecessary riskfor the patient. Currently, echocardiographic and radionuclide techniques are the most established methods for the assessment of presence and extent of viable myocardium. Magnetic resonance imaging (MRI) also provides multiple approaches for determining viability of acute ischemically injured and hibernating myocardium. MRI can assess contractile reserve in a manner similar to echocardiography. Additionally, contrast-enhanced MRI can characterize myocardial ischemic injury, including the ability to discriminate viable from nonviable zones. Several new contrast media have been introduced for this purpose. This review addresses the progress toward the goal of defining myocardial viability based on MR techniques and focuses on the current and future role of MR in the assessment of viable myocardium.

Chemoembolization of liver tumor in a rabbit model: assessment of tumor cell death with diffusion-weighted MR imaging and histologic analysis.

PURPOSE: To assess the efficacy of chemoembolization of liver tumors by determining the fraction of viable tumor cells remaining after treatment with use of diffusion magnetic resonance (MR) imaging and histologic analysis. MATERIALS AND METHODS: VX2 tumor was grown in the livers of 12 rabbits. Animals were divided into a chemoembolization group and an untreated group. Conventional, perfusion, and diffusion MR imaging was performed on all rabbits. Histopathologic analysis of explanted livers was performed to document tumor cell death and measure Bcl-2 levels (inhibitor of apoptosis). RESULTS: Diffusion-weighted MR imaging delineated zones of tumor cell death as regions of lower signal intensity in both groups. Apparent diffusion coefficients were significantly greater in the area of tumor necrosis than in the area of viable tumor. Histologic analysis demonstrated a significantly lower percentage of viable cells in the treated group (<1%) than in the control group (55%). Bcl-2 expression detected within the viable areas of the tumor was greater in the treated group than in the control group. CONCLUSIONS: Chemoembolization causes extensive tumor cell destruction. Diffusion MR imaging can detect tumor cell death and can be used to assess the efficacy of chemoembolization. Bcl-2 was expressed in the treated group, suggesting an apoptotic pathway of cell death.

Coronary flow reserve: assessment by magnetic resonance imaging.

Coronary angiography has been the standard method for quantifying the severity of coronary artery stenosis, however its physiological relevance by angiography is imperfect. At present velocity-encoded cine phase contrast MRI is a non invasive technique that can provide accurate assessment of coronary flow volume and coronary flow reserve, validated in animal and human studies by Doppler flow measurement. MRI may be recognized as a comprehensive, widely available technique independent of any nuclear tracer or contrast media, for evaluation of the presence and physiological significance of a variety of heart diseases which compromise coronary flow reserve.

[Visual assessment or quantitative measurement of coronary stenoses: significance for "prima vista"-PTCA]. / Visuelle Einschätzung oder quantitative Vermessung von Koronarstenosen: Bedeutung für die "prima vista"-PTCA.

In 300 patients with 339 coronary lesions the percent diameter stenosis (%-DS) was assessed both by visual estimation and by digital quantitative coronary angiography (DQCA) by use of an on-line computer work-station. The decision for coronary angioplasty in the same setting ("prima vista"-PTCA) was based on history, evidence of ischemia and visual estimation of %-DS. DQCA measurements of the 339 stenoses revealed a normal distribution of lesion severity with a mean of 58.4 +/- 11.3%. In contrast to DQCA visual estimation led to a bimodal distribution with a nadir at approximately 55% between two peaks at approximately 45% and approximately 75% and a mean of 70.5 +/- 19.6%. Visual estimation underestimated lesions in the range of 30-55% and overestimated the %-DS between 55-99%. Visual estimation revealed a %-DS > or = 60% in 251 stenoses (74.0%) of the 339 lesions, an estimate that led to subsequent "prima vista"-PTCA. Conversely, DQCA revealed only 184 stenoses (54.3%) with a %-DS > or = 60%; thus, 86 stenoses (25.3%) did not meet the morphologic indication criteria for PTCA. The bimodal distribution of stenosis severity according to visual analysis with an overestimation of borderline stenosis severity reflects at tendency for "self-referral" of patients for PTCA. DQCA serves as an objective tool in the decision-making process for PTCA and may reduce "cosmetic" interventions or justify to defer PTCA. Especially in the selection process for "prima vista"-PTCA DQCA-quantification of stenosis severity is recommended.

Laparoscopic cholecystectomy-related bile duct injuries: a health and financial disaster.

OBJECTIVE: This study was designed to evaluate the total costs associated with repair of laparoscopic cholecystectomy (LC)-related bile duct injuries. SUMMARY BACKGROUND DATA: The popularity of LC with both patients and surgeons is such that this procedure now exceeds open cholecystectomy by a ratio of approximately 4 to 10:1. However, costs associated with LC-related injuries, particularly regarding treatment patterns, have up to now not been explored fully. METHODS: The complete hospital and interventional radiology (IR) billing records for 49 patients who have completed treatment for laparoscopic cholecystectomy-related bile duct injuries were divided into 8 categories. These records were totaled for comparison of costs between patient groups that experienced different injuries and treatment patterns. RESULTS: Patients with LC-related bile duct injuries were billed a mean of $51,411 for all care related to repair of their bile duct injury. Patients incurred an average of 32 days of inpatient hospitalization and 10 outpatient care days. Postoperative treatment included long-term chronic biliary intubation averaging 378 days. Two patients (4%) died as a result of their LC-related complications. Patients with bile duct injuries that were recognized immediately at the time of the initial surgery ultimately experienced a total cost for their repair and hospitalization of 43% to 83% less than for patients in whom recognition of the injury was delayed (p < 0.019 to 0.070). In addition, the total hospitalization and outpatient care days was reduced by as much as 76% with early recognition of an iatrogenic injury. CONCLUSIONS: Repair of cholecystectomy-related bile duct injuries can run 4.5 to 26.0 times the cost of the uncomplicated procedure and carries a significant mortality rate. Intraoperative recognition of such an injury with immediate conversion to an open procedure for definitive repair can result in significant cost savings and relates directly to a decreased morbidity, mortality, length of hospitalization, and number of outpatient care days.