Efficacy of pre-scan beta-blockade and impact of heart rate on image quality in patients undergoing coronary multidetector computed tomography angiography

OBJECTIVE: While beta-blockers are routinely administered to patients prior to coronary computed tomography angiography (CTA), their effectiveness is unknown. We therefore assessed the efficacy of beta-blockade with regards to heart rate (HR) control and image quality in an unselected patient cohort. METHODS: We studied 150 consecutive patients (104 men/46 female; mean age, 56+/-13 years) referred for coronary CTA. Intravenous metoprolol (5-20mg) was administered to patients with a HR >65 beats per minute (bpm). The goal HR was defined as an average HR <65 bpm without a single measurement above 68 bpm. RESULTS: Overall, 45% (68/150) of patients met the HR criteria for beta-blocker administration of which 76% (52/68) received metoprolol (mean dose 12+/-10mg). Of the 52 patients who received beta-blocker versus the 98 who did not, 18 (35%) versus 62 (64%) patients achieved the goal HR, respectively. All patients who achieved the target HR had an evaluable CTA while five patients who did not achieve the target HR had at least one non-evaluable coronary artery due to motion artifact. There was also a significant reduction in any motion artifact among those who achieved the goal HR as compared to those who did not (p=0.001). Logistic regression revealed an increase in the odds of stair step artifact of 11.6% (95% CI: 2.4% decrease, 27.5% increase) per 1 bpm increase in the standard deviation of scan HR. CONCLUSION: Overall, efficacy of beta-blocker administration to reach target HR is limited. Improvements in CT scanner temporal resolution are mandatory to achieve consistently high image quality independent of HR and beta-blocker administration.     

A systematic review on diagnostic accuracy of CT-based detection of significant coronary artery disease

OBJECTIVES: Systematic review of diagnostic accuracy of contrast enhanced coronary computed tomography (CE-CCT). BACKGROUND: Noninvasive detection of coronary artery stenosis (CAS) by CE-CCT as an alternative to catheter-based coronary angiography (CCA) may improve patient management. METHODS: Forty-one articles published between 1997 and 2006 were included that evaluated native coronary arteries for significant stenosis and used CE-CCT as diagnostic test and CCA as reference standard. Study group characteristics, study methodology and diagnostic outcomes were extracted. Pooled summary sensitivity and specificity of CE-CCT were calculated using a random effects model (1) for all coronary segments, (2) assessable segments, and (3) per patient. RESULTS: The 41 studies totaled 2515 patients (75% males; mean age: 59 years, CAS prevalence: 59%). Analysis of all coronary segments yielded a sensitivity of 95% (80%, 89%, 86%, 98% for electron beam CT, 4/8-slice, 16-slice and 64-slice MDCT, respectively) for a specificity of 85% (77%, 84%, 95%, 91%). Analysis limited to segments deemed assessable by CT showed sensitivity of 96% (86%, 85%, 98%, 97%) for a specificity of 95% (90%, 96%, 96%, 96%). Per patient, sensitivity was 99% (90%, 97%, 99%, 98%) and specificity was 76% (59%, 81%, 83%, 92%). Heterogeneity was quantitatively important but not explainable by patient group characteristics or study methodology. CONCLUSIONS: Current diagnostic accuracy of CE-CCT is high. Advances in CT technology have resulted in increases in diagnostic accuracy and proportion of assessable coronary segments. However, per patient, accuracy may be lower and CT may have more limited clinical utility in populations at high risk for CAD.     

Assessment of left ventricular function with 16- and 64-slice multi-detector computed tomography

BACKGROUND: Important to the risk stratification and management of cardiac patients is the assessment of left ventricular function (LVEF), thus imaging modalities which can provide both anatomical and functional data is desirable. Electrocardiographic (ECG) gated multi-detector computed tomographic (MDCT) images may provide accurate assessment of LV ejection fraction, volume and dimensions but have shown systemic errors in the past due to slow gantry rotation speed. METHODS: Between May 2004 and January 2005, 306 patients underwent ECG-gated cardiac CT studies at the Massachusetts General Hospital. Patients with available CT data sets and a recent (within 3 months) ECHO and/or SPECT perfusion imaging were included in the study. ECG-gated data sets were acquired either with a 16-slice or with a 64-slice MDCT. Functional MDCT data sets were reconstructed in 10 cardiac phases (5-95%) with 1.5mm slices. Images were processed and interpreted by two observers blinded to ECHO and SPECT results. RESULTS: A total of 69 patients had MDCT and ECHO or SPECT within 3 months (33 had 16-slice and 36 had 64-slice MDCT). There was fair correlation between LVEF measured by 16-slice MDCT and 'ECHO or SPECT' (62+/-10% vs. 62+/-10%; r=0.56). There was poor correlation between LVEF measured by 16-slice MDCT and ECHO (64+/-10% vs. 59+/-11%; r=0.26) and there was good correlation between LVEF measured by 16-slice MDCT and SPECT (62+/-11% and 64+/-9%, respectively; r=0.76). There was very good correlation between LVEF measured by 64-slice MDCT and 'ECHO or SPECT' (57+/-15% vs. 58+/-13%; r=0.86). There was very good correlation between LVEF measured by MDCT and ECHO (56+/-14% vs. 54+/-15%; r=0.89) and between LVEF measured by 64-slice MDCT and SPECT (60+/-13% and 60+/-14%, respectively; r=0.90). CONCLUSION: The assessment of LVEF and LV dimensions with 64-slice MDCT provide values which are similar to those obtained by echocardiography and Tc-99m gated SPECT. The accuracy of the 64-slice MDCT with a gantry rotation speed of 330ms (when compared to ECHO and SPECT) may be superior to that of the 16-slice MDCT at 420ms gantry rotation.     

Influence of rinsing and expectoration after toothbrushing on fluoride dose and ingested amount by use of conventional and children's fluoride dentifrices

The purpose of this study was to assess the amount of ingested fluoride and the fluoride dose to which children are subjected during toothbrushing with a conventional dentifrice (1500 ppm F) and a children's dentifrice with special flavor (1100 ppm F) and evaluate the influence of rinsing and expectoration after brushing. Six brushings followed by 6 residue collections (3 per dentifrice) were performed by 42 Brazilian children (aged 20 to 30 months). The concentration of fluoride in the residues and dentifrices was determined. The amount ingested was obtained by the difference principal. 64.3% of the children did not expectorate or rinse after brushing. For both toothpastes, no significant difference was found for fluoride doses comparing children that rinsed to those that did not rinse (p > or = 0.05). When children's toothpaste was used, children who did not expectorate were exposed to a higher dose than those who did expectorate (p = 0.032). The same was not observed when conventional toothpaste (p = 0.081) was used. In conclusion, rinsing and expectoration after brushing had no influence on the dose of fluoride to which children were exposed by use of the dentifrices. However, expectoration was directly associated to the fluoride dose when the children's dentifrice was used.     

Effect of sucrose on the selection of mutans streptococci and lactobacilli in dental biofilm formedin situ

Microorganisms are selected in dental biofilm by the acidic environment created by sugar fermentation, but the effect of extracellular polysaccharide (EPS) on the counts of cariogenic bacteria is not clear. Dental biofilm was formed in situ for 13 days under exposure 8 times a day to distilled-deionized water, glucose + fructose or sucrose solutions. Mutans streptococci (MS) counts were not different among the groups, but lactobacilli (LB) were significantly higher in glucose + fructose and sucrose groups, without significant difference between them, irrespective of the higher insoluble EPS concentration in the sucrose biofilm matrix. The data suggest that exposure to sugar is more relevant for the predominance of LB in dental biofilm than for MS and that insoluble EPS does not change the counts of these microorganisms in the biofilm.     

Usefulness of coronary computed tomographic angiography to assess suitability for revascularization in patients with significant coronary artery disease and angina pectoris

Coronary computed tomographic angiography (CTA) accurately excludes the presence of coronary stenoses in selected patient populations. However, it remains unclear whether coronary CTA has the potential to replace invasive coronary angiography as a tool to assess a patient's suitability for revascularization as determined by the characterization of lesion morphology in patients with significant coronary artery disease. Coronary CTA (64-slice computed tomography) was performed before invasive coronary angiography in 29 patients. We evaluated the accuracy of CTA for the detection of complex lesion morphology, including the presence of severe calcium, total occlusions, and ostial or bifurcation location, and compared the results with those of invasive angiography. On CTA, 10 of 69 lesions (15%) were not evaluable for any feature of complex lesion morphology. Of the evaluable lesions, CTA detected >or=1 feature of complexity in 58% of lesions, corresponding to a sensitivity of 88% (23 of 26) and a specificity of 83% (24 of 29). For those single features, the sensitivity of CTA was 100% for the presence of severe calcium, 93% for total occlusions, and 60% and 80% for the detection of ostial and bifurcation lesions, respectively. The specificity was high for total occlusions (97%), ostial lesions (97%), and bifurcations (100%). It was moderate (85%) for severe calcium. Severe calcium precluded the evaluation of other features of complex lesion morphology in 6 lesions (11%). In conclusion, invasive selective coronary angiography remains the cornerstone to assess a patient's suitability for revascularization given the high proportion of unevaluable segments and segments with severe calcium that precluded adequate revascularization planning on CTA.     

Combining radiation therapy and androgen deprivation for localized prostate cancer-a critical review

Interest has been increasing in the use of androgen deprivation therapy (ADT) combined with radiation therapy (RT) in the management of localized prostate cancer. Preclinical studies have provided some rationale for the use of this combination. In patients with high-risk disease, the benefit of a combined approach, with the addition of adjuvant hormonal therapy, is supported by results of randomized trials. In contrast, for patients with low-risk disease, there is no obvious therapeutic advantage except for cytoreduction. The usefulness of short-term hormonal therapy in association with rt for intermediate-risk patients is still debatable, particularly in the context of doseescalated RT. The optimal timing and duration of ADT, in the neoadjuvant and adjuvant settings alike, are still under investigation. In view of the potential side effects with ADT, further studies are being performed to better identify subsets of patients who will definitely benefit from this therapy in combination with rt.     

An improved technique for controlling bleeding during simple retropubic prostatectomy: a randomized controlled study

OBJECTIVE: To compare two techniques of open prostatic adenectomy (OPA) for controlling bleeding, as OPA is the most effective surgical method for alleviating obstructive symptoms related to benign prostatic hyperplasia (BPH) but there is always a risk of peri-operative bleeding. PATIENTS AND METHODS: The study comprised a prospective and randomized analysis of 62 men with BPH who consecutively had OPA between January 2002 and September 2004. Two techniques were used: in group 1, patients had the Millin modified retropubic prostatectomy, and in group 2 they had a classical transvesical prostatectomy. Blood loss during and after surgery was analysed. RESULTS: The median (range) blood loss during surgery was 362 (50-700) and 640 (200-1500) mL for groups 1 and 2, respectively (P = 0.007). The mean (sd) decrease in haemoglobin level from before to 1 day after surgery was 1.76 (0.31) and 3.15 (0.33) g/dL for groups 1 and 2, respectively (P < 0.001). When comparing the first and third days after surgery, there were no further significant decreases in levels for group 1, at 0.15 (0.31) g/dL (P = 0.175), but there was a significant decrease for group 2, at 0.74 (0.33) g/dL (P = 0.031). There was a similar decrease in haematocrit levels. While three patients from group 2 required a blood transfusion, only one from group 1 had to be transfused. CONCLUSION: The Millin technique, as modified by one of the present authors, can significantly control bleeding during and after surgery, and reduce transfusion rates, when compared to the classic transvesical prostatectomy.