Conduit Flow Compensates for Impaired Left Atrial Passive and Booster Functions in Advanced Diastolic Dysfunction

BACKGROUND

Quantification of left atrial (LA) conduit function and its contribution to left ventricular (LV) filling is challenging because it requires simultaneous measurements of both LA and LV volumes. The functional relationship between LA conduit function and the severity of diastolic dysfunction remains controversial. We studied the role of LA conduit function in maintaining LV filling in advanced diastolic dysfunction.

METHODS

We performed volumetric and flow analyses of LA function across the spectrum of LV diastolic dysfunction, derived from a set of consecutive patients undergoing multiphasic cardiac computed tomography scanning (n=489). From LA and LV time-volume curves, we calculated 3 volumetric components: (1) early passive emptying volume; (2) late active (booster) volume; and (3) conduit volume. Results were prospectively validated on a group of patients with severe aortic stenosis (n=110).

RESULTS

The early passive filling progressively decreased with worsening diastolic function (P<0.001). The atrial booster contribution to stroke volume modestly increases with impaired relaxation (P=0.021) and declines with more advanced diastolic function (P<0.001), thus failing to compensate for the reduction in early filling. The conduit volume increased progressively (P<0.001), accounting for 75% of stroke volume (interquartile range, 63-81%) with a restrictive filling pattern, compensating for the reduction in both early and booster functions. Similar results were obtained in patients with severe aortic stenosis. The pulmonary artery systolic pressure increased in a near-linear fashion when the conduit contribution to stroke volume increased above 60%. Maximal conduit flow rate strongly correlated with mitral E-wave velocity (r=0.71; P<0.0001), indicating that the increase in mitral E wave in diastolic dysfunction represents the increased conduit flow.

CONCLUSIONS

An increase in conduit volume contribution to stroke volume represents a compensatory mechanism to maintain LV filling in advanced diastolic dysfunction. The increase in conduit volume despite increasing LV diastolic pressures is accomplished by an increase in pulmonary venous pressure.

Ser194Leu DSG2 mutation, associated with arrhythmogenic left ventricular cardiomyopathy and ventricular tachycardia

INTRODUCTION

Arrhythmogenic cardiomyopathy (AC) is an inherited cardiomyopathy characterized by fibro-fatty replacement of cardiomyocytes, leading to life-threatening ventricular arrhythmia and heart failure. Pathogenic variants of desmoglein2 gene (DSG2) have been reported as genetic etiologies of AC. In contrast, many reported DSG2 variants are benign or variants of uncertain significance. Correct genetic variant classification is crucial for determining the best medical therapy for the patient and family members.

METHODS

Pathogenicity of the DSG2 Ser194Leu variant that was identified by whole exome sequencing in a patient, who presented with ventricular tachycardia and was diagnosed with AC, was investigated by electron microscopy and immunohistochemical staining of endomyocardial biopsy sample.

RESULTS

Electron microscopy demonstrated a widened gap in the adhering junction and a less well-organized intercalated disk region in the mutated cardiomyocytes compared to the control. Immunohistochemical staining in the proband diagnosed with AC showed reduced expression of desmoglein 2 and connexin 43 and intercalated disc distortion. Reduced expression of DSG2 and Connexin 43 were observed in cellular cytoplasm and gap junctions. Additionally, we detected perinuclear accumulation of DSG2 and Connexin 43 in the proband sample.

CONCLUSION

Ser194Leu is a missense pathogenic mutation of DSG2 gene associated with arrhythmogenic left ventricular cardiomyopathy.

Radiological findings in poisoning by synthetic cannabinoids adulterated with brodifacoum

OBJECTIVES

Severe coagulopathy due to consumption of synthetic cannabinoids adulterated with brodifacoum, a long-acting anticoagulant, is an emerging worldwide hazard. Here, we review the spectrum of imaging findings in adulterated cannabinoid poisoning.

MATERIALS AND METHODS

In this retrospective study, we used the Israeli Poison Information Center database to identify patients with cannabinoid-associated coagulopathy who presented to the Rambam Health Care Campus, where most patients were treated during an outbreak in northern Israel between September 2021 and June 2022. All relevant imaging studies for these patients were reviewed. We estimated the sensitivity of findings for cannabinoid-associated coagulopathy. Associations between a continuous variable and a dichotomous outcome were assessed with the Mann-Whitney U test.

RESULTS

We identified 48 patients (mean age 40 years ± 9 [SD], 43 males) with 54 hospitalizations due to cannabinoid-associated coagulopathy. Symptomatic hemorrhage was documented in 50 (93%) cases at presentation, most of whom (78%) had hemorrhage from multiple systems. The most common bleeding site was the genitourinary collecting system, with a characteristic sign of suburothelial bleeding in 16/18 of performed abdominal CTs (sensitivity 89% [CI 65-99%] for cannabinoid-associated coagulopathy). Intramural bowel hematomas were noted in 70% (7/10) of CTs of patients with gastrointestinal bleeding. Incidental bleeding sites were identified on imaging in 24% of patients. An increased number of bleeding sites was associated with need for vasopressors (difference in bleeding sites 3.00 [95% CI 0.99-4.00], p = 0.026).

CONCLUSION

CT plays a key role in the diagnosis and work-up of adulterated cannabinoid-associated coagulopathy. Characteristic signs include suburothelial hemorrhage and intramural bowel hematomas.

CLINICAL RELEVANCE STATEMENT

Recognition of radiological signs of adulterated synthetic cannabinoid-associated coagulopathy is critical for optimizing outbreak control on the public health level and ensuring timely treatment on the individual patient level.

KEY POINTS

• Severe coagulopathy due to consumption of synthetic cannabinoids adulterated with brodifacoum, a long-acting anticoagulant, is an emerging worldwide threat. • Characteristic imaging signs include suburothelial bleeding, intramural bowel hematomas, and rare incidental bleeding sites. • Imaging has a pivotal role in optimizing outbreak control and ensuring timely and appropriate treatment.

Left atrial function by cardiac computed tomography is a predictor of heart failure and cardiovascular death

OBJECTIVES

We sought to evaluate cardiac CT angiography (CCTA)-based assessment of left atrial (LA) function as a predictor of hospitalizations for heart failure (HF) and cardiovascular (CV) mortality.

METHODS

LA function was evaluated using automatic derivation of LA volumes to calculate LA total emptying fraction (LATEF) in 788 consecutive patients with normal sinus rhythm who had undergone spiral CT scans. The relationship between LATEF evaluated by CCTA and the composite endpoint of admission for HF or CV mortality was analyzed using Cox models.

RESULTS

During a median follow-up of 4 years, there were 100 events, 62 HF hospitalizations, and 38 cardiovascular deaths. Mean LATEF was 30.7 ± 10.7% and 40.5 ± 11.2% in patients with and without events, respectively (p < 0.0001). A high LATEF (upper tertile > 46%) was associated with a very low event rate (3.5% at 6 years [95% CI 1.7-7.1%]). The adjusted HR for HF or CV mortality was 4.37 (95% CI 1.99-9.60) in the lowest LATEF tertile, and 2.29 (95% CI 1.03-5.14) in the middle tertile, relative to the highest tertile. For the endpoint of HF alone, adjusted HR for the lowest LATEF tertile was 5.93 (95% CI 2.23-15.82) and for the middle tertile 2.89 (95% CI 1.06-7.86). The association of LATEF with outcome was similar for patients with both reduced and preserved left ventricular (LV) ejection fraction (P_interaction = 0.724). Reduced LATEF was associated with a high event rate, even when coupled with normal LA volume.

CONCLUSION

CCTA-derived LA function is a predictor of HF hospitalization or CV death, independent of clinical risk factors, LA volume, and LV systolic function.

KEY POINTS

• Left atrial function can be automatically derived from cardiac CTA scans. • Cardiac CTA-derived left atrial function is a predictor of hospitalization for heart failure and cardiovascular death. • Evaluation of left atrial function could be useful in identifying patients at risk of heart failure.

New technique: removal of embedded esophageal partially covered stent by endoscopic sub-stent space dissection

Both fully (FCSEMS) and partially (PCSEMS) covered self-expandable metal stents are used for the endoscopic management of leaks, perforations, and fistulas. PCSEMS have lower migration rates as their uncovered flanges allow for anchorage into the surrounding tissue, but this consequently makes them difficult to be removed, with reported cases of esophageal perforation during the removal of the embedded PCSEMS. Stent-in-stent technique is mostly used, where a FCSEMS is placed co-axially into an existing PCSEMS causing pressure necrosis and facilitating subsequent removal of both stents. This technique, although effective, is expensive, requiring the use of a second stent. In this report, we describe a series of 3 patients with embedded PCSEMS removed by a new endoscopic technique, i.e., endoscopic sub-stent space dissection, without using a second stent.

Assessment of mitral regurgitation by 3-dimensional proximal flow convergence using magnetic resonance imaging: comparison with echo-Doppler

To test the feasibility of assessing mitral regurgitation (MR) severity using cardiac magnetic resonance (CMR) 4D velocity vectors to quantify regurgitant volume (RVol) by analysis of the proximal flow convergence, compared to Doppler based proximal isovelocity surface area (PISA) and CMR volume-based methods. In a prospectively designed study, 27 patients with various grades of MR underwent CMR and echo-Doppler on the same day. By CMR, multiple slices were obtained parallel to the mitral valve by phase-contrast imaging, using 3D velocity vectors, as well as short-axis cine images for left and right ventricular volume measurements. Using dedicated software developed in our laboratory, the perimeter of the proximal flow convergence region was semi-automatically measured for each temporal phase, and for each short-axis slice. The CMR-PISA RVol was calculated as the sum of PISA perimeters throughout systole, multiplied by slice width. For comparison, CMR-volumetric RVol was calculated by 2 methods: Volumetric (difference between left and right ventricular stroke volumes) and Flow-based (stroke volume -aortic flow). Echo-PISA RVol was calculated by echo-Doppler based PISA method. RVol by CMR-PISA correlated highly with echo-PISA (r = 0.87) and with CMR-volumetric (r = 0.86) and CMR-flow (r = 0.72). For comparison Doppler-RVol and CMR-volume-based RVol had r = 0.83. On average CMR-PISA was 16 ± 25 ml less than echo-PISA, but 12 ± 22 ml larger than CMR-volumetric RVol. The observed 3D shape of the PISA envelope by 4D-CMR resembled a hemiellipsoid rather than a hemisphere. This feasibility study suggests that CMR-based 4D-PISA may be able to assess MR severity quantitatively without any geometric assumptions.

Multimodality Image Fusion with PSMA PET/CT and High-Intensity Focused Ultrasound Focal Therapy for Primary Diagnosis and Management of Prostate Cancer: A Planned Research Initiative

Recent developments in diagnostic imaging herald a new approach to diagnosis and management of prostate cancer. Multimodality fusion that combines anatomic with functional imaging data has surpassed either of the two alone. This opens up the possibility to "find and fix" malignancy with greater accuracy than ever before. This is particularly important for prostate cancer because it is the most common male cancer in most developed countries. This article describes technical advances under investigation at our institution and others using multimodality image fusion of magnetic resonance imaging (MRI), transrectal ultrasound (TRUS), and PSMA PET/CT (defined as the combination of prostate-specific membrane antigen [PSMA], positron emission tomography [PET], and computed tomography [CT]) for personalized medicine in the diagnosis and focal therapy of prostate cancer with high-intensity focused ultrasound (HiFUS).

Automatic Estimation of Optimal Deployment of Transcatheter Aortic Valve Implantation Using Computed Tomography

BACKGROUND

A comparison was made between the accuracy of and time saved by using novel automated software for pre-procedural computed tomography (CT) planning before transcatheter aortic valve implantation (TAVI) and manual methods. Preprocedural CT to assess aortic annulus dimensions and predict the optimal C-arm implant angle before TAVI can reduce complications related to incorrect prosthesis sizing and positioning.

METHODS

A total of 61 consecutive patients underwent TAVI using either the SAPIEN XT or CoreValve prosthesis. Pre-procedural CT scans were analysed using three methods: automatic; semi-automatic; and manual. For each method, annular dimensions were measured and the optimal implantation angle was predicted. After TAVI the actual post-deployment angle orthogonal to the prosthesis was determined using aortic fluoroscopy. The difference between the predicted angle by CT and the measured post-deployment angle was calculated for each method.

RESULTS

For all methods the mean angular difference with the actual post-deployment angle was similar at ~9 ± 7°. There was a significant difference between the SAPIEN XT (6.6 ± 5.8°) and CoreValve (11.5 ± 6.9°, p <0.001) prostheses due to a consistently greater left anterior oblique and caudal angulation for the CoreValve. Although the annular area correlated well among all methods, 'automatic' results were consistently larger than 'manual' results. Interobserver variability was low for all measures. The fully automatic method saved 98 s, and the semiautomatic method 40 s per case.

CONCLUSIONS

The use of automatic software enabled a rapid and accurate prediction of implantation angles, though results differed for specific manufacturers. Annular areas were overestimated by the automatic method, and thus required manual adjustments.

Pyogenic Granuloma: Possible Cause for Macroscopic Hematuria in Children

Pyogenic granuloma (PG) is a benign, vascular tumor that is rarely reported in the urinary tract of pediatric population. Herein we present a case of a child followed up for recurrent painless macroscopic hematuria. We performed ureteroscopy, and a whitish lesion was discovered in the upper calyx of the right kidney. The lesion resected endoscopically, and microscopic examination of the lesion was consistent with PG. It is important for pediatricians and urologists to properly recognize PG as a possible source of hematuria in the pediatric population.

Impact of computed tomography image and contact force technology on catheter ablation for atrial fibrillation

AIM: To investigate the impact of using computed tomography (CT) and contact force (CF) technology on recurrence of atrial tachyarrhythmia after atrial fibrillation (AF) ablation.

METHODS: This non-randomized study included 2 groups of patients. All patients had symptomatic recurrent paroxysmal or persistent AF and were treated with at least 1 anti arrhythmic medication or intolerant to medication. The first group included 33 patients who underwent circumferential pulmonary veins isolation (PVI) for AF during 2012 and 2013 guided by CT image integration (Cartomerge, Biosense Webster, Diamond Bar, CA, United States) of left atrium and pulmonary veins into an electroanatomic mapping (EAM) system (CT group) using standard irrigated radiofrequency catheter (ThermoCool, Carto, Biosense Webster, Diamond Bar, CA, United States) or irrigated catheter with integrated CF sensor (Smart Touch, Carto, Biosense Webster, Diamond Bar, CA, United States). The second group included immediately preceding 32 patients who had circumferential PVI by standard irrigated catheter (ThermoCool) using only EAM (Carto) system (EAM group). Linear lesions were performed according to the discretion of operator.

RESULTS: Sex, age, and persistent AF were not different between groups. PVI was achieved in all patients in both groups. Linear ablations including cavo-tricuspid isthmus and or roof line ablation were not different between groups. Free of atrial tachyarrhythmia during follow-up of 24 mo was significantly higher among CT group compared to EAM group (81% vs 55%; respectively; P = 0.027). When 11 patients from CT group who had ablation using Smart Touch catheter were excluded, the difference between CT group and EAM became non significant (73% vs 55%; respectively; P = 0.16). Sub analysis of CT group showed that patients who had ablation using Smart Touch catheter tend to be more free of atrial tachyarrhythmia compared to patients who had ablation using standard irrigated catheter during follow-up (100% vs 73%; respectively; P = 0.07). Major complications (pericardial effusion, cerebrovascular accident/transient ischemic attack, vascular access injury requiring intervention) did not occurred in both groups.

CONCLUSION: These preliminary results suggest that CT image integration and CF technology may reduce the recurrence of atrial tachyarrhythmia after catheter ablation for AF.

Outflow tract ventricular arrhythmia originating from the aortic cusps: our approach for challenging ablation

BACKGROUND

Ablation of outflow flow ventricular arrhythmia (VA) originating from aortic cusps can be challenging. The aim of this study was to describe our approach for this ablation.

METHODS

All patients with outflow VA suspected to originate from aortic cusps according to ECG or after failed ablation from right ventricular outflow tract (RVOT) underwent cardiac CT and radiofrequency ablation. CT image of aortic cusps and coronary arteries was integrated into electroanatomic mapping system by point (left main ostium)-based registration. Ablation was performed at the earliest activation site.

RESULTS

Ten patients were included in this case cohort. The ablation catheter was easily maneuvered above and below the aortic valve after registration. Two patients who had previous failed ablation of RVOT focus had successful ablation at right coronary cusp (RCC) and at left coronary cusp (LCC). A patient who had previous failed ablations of RVOT and LCC focuses had successful ablation at RCC-LCC junction. A patient who had previous failed ablation at LCC had successful ablation at RCC-LCC junction. Three patients had successful ablation at RCC-LCC junction, and one patient at LCC. One patient had successful ablation at anterior interventricular vein-great cardiac vein junction. One patient had successful ablation at non-coronary cusp. During follow-up (12-30 months), one patient had recurrence of VA controlled by flecainide. The remaining patients were free of VA without medications.

CONCLUSIONS

Catheter ablation of VA originating from aortic cusps is safe and effective. CT image integration into electroanatomic mapping system can be helpful in this challenging ablation.

Assessment of left sided filling dynamics in diastolic dysfunction using cardiac computed tomography

BACKGROUND

Left ventricular (LV) diastolic dysfunction (DD) often accompanies coronary artery disease but is difficult to assess since it involves a complex interaction between LV filling and left atrial (LA) emptying.

OBJECTIVE

To characterize simultaneous changes in LA and LV volumes using cardiac computed tomography (CT) in a group of patients with various grades of DD based on echocardiography.

METHODS

We identified 35 patients with DD by echocardiography, who had also undergone cardiac CT, and 35 age-matched normal controls. LV and LA volumes were measured every 10% of the RR interval, using semi-automatic software. From these, - systolic, early-diastolic and late-diastolic volume changes were calculated, and additional parameters of diastolic filling derived. Conduit volume was defined as the difference between the LV and LA early-diastolic volume change.

RESULTS

Patients with DD had significantly larger LV mass, and LA volumes, reduced early emptying volumes and increased conduit volume as percent of early LV filling (All p<0.001). LA function, manifesting as total emptying fraction (LATEF), decreased proportionately with worsening grades of DD (p<0.001). LA contractile function was maintained until advanced grade-3 DD. By receiver operating characteristic analysis, LATEF had an AUC of 0.88 to separate between normals and DD. At a threshold of <42.5%, LATEF has 97% sensitivity and 69% specificity to detect DD.

CONCLUSIONS

DD is characterized by reduced LA function and an alteration in the relative contributions of the atrial emptying and conduit volume components of early LV filling. In patients undergoing cardiac CT, it is possible to identify the presence and severity of DD.

Multidetector computed tomography predictors of late ventricular remodeling and function after acute myocardial infarction

BACKGROUND

Despite advent of rapid arterial revascularization as 1st line treatment for acute myocardial infarction (AMI), incomplete restoral of flow at the microvascular level remains a problem and is associated with adverse prognosis, including pathological ventricular remodeling. We aimed to study the association between multidetector row computed tomography (MDCT) perfusion defects and ventricular remodeling post-AMI.

METHODS

In a prospective study, 20 patients with ST-elevation AMI, treated by primary angioplasty, underwent arterial and late phase MDCT as well as radionuclide scans to study presence, size and severity of myocardial perfusion defects. Contrast echocardiography was performed at baseline and at 4 months follow-up to evaluate changes in myocardial function and remodeling.

RESULTS

Early defects (ED), late defects (LD) and late enhancement (LE) were detected in 15, 7 and 16 patients, respectively and radionuclide defects in 15 patients. The ED area (r=0.74), and LD area (r=0.72), and to a lesser extent LE area (r=0.62) correlated moderately well with SPECT summed rest score. By univariate analysis, follow-up end-systolic volume index and ejection fraction were both significantly related to ED and LD size and severity, but not to LE size or severity. By multivariate analysis, end-systolic volume index was best predicted by LD area (p<0.05) and ejection fraction by LD enhancement ratio.

CONCLUSIONS

LD size and severity on MDCT are most closely associated with pathological ventricular remodeling after AMI and may thus play a role in early identification and treatment of this condition.

Hybrid cardiac SPECT/64-slice CTA-derived LV function parameters: correlation and reproducibility assessment

The purpose of this study is to define the relationship between SPECT and CTA measured parameters of left ventricular (LV) function and volumes obtained in a single session using SPECT/64-slice CT hybrid imaging device, and in addition, to assess the reproducibility of LV parameters measured using 64-slice CTA.

MATERIALS AND METHODS

Seventy-six patients with suspected or known coronary artery disease underwent cardiac CTA and GSPECT in one session using a hybrid SPECT/CT device. LV end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) were measured on each component of the hybrid device. For the CTA component, these parameters were re-measured by the same investigator and by a second investigator with an interval of 3-54 weeks. Corresponding GSPECT and CTA measured parameters were compared. For CTA, intra-observer and inter-observer variability of LV function and volume measurements were calculated.

RESULTS

A very good correlation was found between the GSPECT and CTA measured LVEF (r=0.81), ESV (r=0.90) and EDV (r=0.82). There was a small positive difference by CTA measured LVEF (3.9+/-14.2%), and more prominent positive differences by CTA measured ESV and EDV (9.8+/-14.8 and 44.9+/-23.1cm(3), respectively). There was excellent reproducibility in the measurements of all parameters with very low intra- and inter-observer variability (r=0.93 for EF and 0.98 for EDV and ESV).

CONCLUSIONS

Although a good correlation was found between the EF measurements obtained from CTA and SPECT, interchangeable use of EF measurements between the two modalities should be done cautiously and interchangeable use of LV EDV and ESV should be avoided.

Feasibility of automatic assessment of four-chamber cardiac function with MDCT: Initial clinical application and validation

BACKGROUND

The ability to perform a simultaneous analysis of ventricular and atrial volumes may provide clinically useful information for diagnosis and prognosis. We aimed to evaluate the feasibility and clinical value of a novel algorithm that performs fully automatic evaluation of the four cardiac chambers and myocardium from gated CT datasets.

METHODS

50 patients were studied-Group 1: 30 consecutive unselected patients, Group 2A: 10 patients after myocardial infarction and Group 2B: 10 normal controls. Fully automatic, segmentation of the heart was performed with a model-based segmentation algorithm requiring no user input other than loading the datasets. Qualitative and quantitative evaluation of segmentation quality was performed. Left ventricular (LV) and right ventricular (RV) stroke volumes (SV) were compared.

RESULTS

Overall, segmentation succeeded in all patients although 11/500 (2.2%) cardiac chambers achieved poor segmentation grading. Correlation coefficients between automatic and manually derived volumes were excellent (r>0.98) for all chambers. Bland-Altman analysis showed minimal bias (-1.0ml, 0.4ml, -1.8ml) for the LV and RV, and right atria, respectively, with mild overestimation of LV myocardial volume (5.2ml). Significant, yet consistent, overestimation of left atrial volume (23.6ml) due to inclusion of proximal pulmonary veins was observed. LV and RV ejection fraction (r=0.91 and 0.98) and SV (r=0.98 and 0.99) also correlated closely with minimal bias (<2%). Most significantly, LV SV (91.0+/-21.6ml) correlated highly with RV SV (81.7+/-18.2ml, r=0.86). Outliers could usually be explained by valvular regurgitation.

CONCLUSIONS

Fully automatic segmentation of all cardiac chambers can be achieved with high accuracy over multiple cardiac phases, enabling reliable comprehensive evaluation of four-chamber cardiac function.

Accuracy of the long-axis area-length method for the measurement of left ventricular volumes and ejection fraction using multidetector computed tomography

BACKGROUND

Multidetector computed tomography (MDCT) is useful for assessing left ventricular (LV) volumes and function. Validation has mainly been carried out using Simpson's method of summing up consecutive short-axis areas. Because the latter method is time-consuming, many users prefer using a quicker method, based on a single view or a pair of views.

OBJECTIVES

To evaluate the accuracy of the long-axis area-length method (AL), which has not been validated for MDCT, using Simpson's method as the gold standard, as well as right anterior oblique LV angiography as a clinical standard.

METHODS

Twenty-three patients admitted with acute chest pain were clinically evaluated with electrocardiogram-gated MDCT and invasive LV angiography. MDCT-based end-diastolic, end-systolic and stroke volumes, and ejection fraction (EF) were calculated using Simpson's method, biplane AL and single-plane AL. For LV angiography, EF was calculated using single-plane AL.

RESULTS

A Bland-Altman analysis showed a close agreement between biplane AL and Simpson's method for EF, with 1% underestimation, 95% CI of +/-11% and a correlation of 0.89. For end-diastolic, end-systolic and stroke volumes, overestimations of 7 mL, 4 mL and 2 mL, and 95% CI of +/-27 mL, +/-15 mL and +/-26 mL, respectively were found. Correlation coefficients were 0.95, 0.97 and 0.82, respectively. Comparisons with LV angiography were considerably weaker. The vertical long-axis AL method by MDCT correlated better with both LV angiography and Simpson's method than the horizontal long-axis AL method.

CONCLUSIONS

The biplane AL method gives results for EF, which correspond closely with the more cumbersome Simpson's method, although volumes are slightly overestimated.

Cardiology consultation as a gatekeeper prior to cardiac multi-detector computed tomography scan

BACKGROUND

Multi-detector computed tomography has advanced enormously and now enables non-invasive evaluation of coronary arteries as well as cardiac anatomy, function and perfusion. However, the role of cardiac MDCT is not yet determined in the medical community and, consequently, many clinically unnecessary scans are performed solely on a self-referral basis.

OBJECTIVES

To prospectively evaluate the role of a cardiologist consultation and recommendation prior to the scan, and the influence on the diagnostic yield of cardiac MDCT.

METHODS

In our center a CT service was initiated, but with the prerequisite approval of a cardiologist before performance of the CT. Each individual who wanted and was willing to pay for a cardiac CT was interviewed by an experienced cardiologist who determined whether cardiac MDCT was the most appropriate next test in the cardiovascular evaluation. Subjects were classified into three groups: a) those with a normal or no prior stress test, no typical symptoms and no significant risk factors of coronary artery disease were recommended to perform a stress test or to remain under close clinical follow-up without MDCT; b) those with an equivocal stress test, atypical symptoms and/or significant risk factors were allowed to have cardiac MDCT; and c) those with positive stress test or clinically highly suspected CAD were advised to go directly to invasive coronary angiography. CT findings were categorized as normal CAD (normal calcium score and no narrowings), < 50% and > 50% CAD.

RESULTS

A total of 254 people were interviewed, and in only 39 cases did the cardiologist approve the CT. However, 61 of the 215, despite our recommendation not to undergo CT, decided to have the scan. Assessment of the 100 cases that underwent MDCT showed a statistically significant better discrimination of significant CAD, according to the cardiologist's recommendation: MDCT not recommended in 3/54 (6%) vs. MDCT recommended in 12/39 (31%) vs. recommended invasive coronary angiography in 4/7 (57%)(P<0.001).

CONCLUSIONS

Detection of coronary calcification, as well as MDCT angiography can provide clinically useful information if applied to suitable patient groups. It is foreseeable that MDCT angiography will become part of the routine workup in some subsets of patients with suspected CAD. Selection of patients undergoing MDCT scans by a cardiologist improves the ability of the test to stratify patients, preventing unnecessary scans in both high and low risk patients.

Evaluating tissue changes with ultrasound during radiofrequency ablation

The purpose of this study was to estimate tissue changes during radiofrequency (RF) ablation by correlating echo frequency shifts and temperature elevations. Experiments were performed on phantoms (tissue mimicking gel) and in-vitro turkey breast. Heating was performed with a modified RF-ablation system. Intermittent RF was applied and the temperature at the electrode tip was continually measured by an embedded thermocouple. Various voltages (10-30V) were applied to achieve a wide range of temperature elevations between 10 and 80 degrees C and ablation sizes between 5 and 27 mm in width. B-mode images and raw data were acquired every 5 s by a modified ultrasound imaging system. The raw data from each line and frame was processed using an algorithm to measure spectral shifts of the echo signals in the power spectrum. The phantom experiments showed positive frequency shifts as the temperature rose, with dependency on the heating rate. A linear relationship (R(2) > 0.96) was found between the RF-applied voltage and the width of the heated area, defined by frequency changes larger than 0.05 MHz. In-vitro experiments showed a correlation (R(2) = 0.84) between the width of the coagulated area and the maximal width of the region with more than 0.12 MHz frequency shifts, but a lower correlation (R(2) = 0.4) between the width of the coagulated area and the temperature elevation. In conclusion, correlation was found between echo frequency shifts and temperature elevations and between echo frequency shifts and the width of the ablated area during intermittent RF ablation. Our results suggest that, with further refinement and validation, ultrasound could be used to measure RF heating and its induced coagulation.

Left ventricular pseudoaneurysm or diverticulum: differential diagnosis and dynamic evaluation by catheter left ventriculography and ECG-gated multidetector CT

We present a case report of the findings of a left ventricular diastolic out pouching in a patient following acute myocardial infarction diagnosed by catheter left ventriculography and electrocardiography (ECG)-gated multidetector computed tomography (MDCT) findings. Left ventriculography demonstrated a small left ventricular diastolic out pouching, while MDCT enabled accurate evaluation of both left ventricular myocardium and lumen, establishing the diagnosis of an intramural small left ventricular pseudoaneurysm. This case illustrates the full capabilities of MDCT in the evaluation of left ventricular pseudoaneurysms.

Misleading positioning of a Foley catheter balloon

Indwelling catheters in the urinary bladder are associated with numerous and various complications, e.g. infection, haemorrhage, epididymo-orchitis and perforation. Abdominopelvic CT is frequently performed in hospitalized patients, with the bladder being included in the examination. Familiarity with the various bladder pathologies and a routine and meticulous search for them are indicated in every case. Moreover, an awareness of certain pitfalls may prevent over-diagnosis and over-treatment. We present a case in which a Foley catheter balloon inflated in a bladder diverticulum simulates sealed bladder perforation with extraluminal location of the balloon. This potentially misleading diagnosis should be considered in the presence of apparent extraluminal position of catheter tip or balloon not substantiated by the clinical presentation.