Research progress on image-based calculation of coronary artery fractional flow reserve / 生物医学工程学杂志

Coronary artery fractional flow reserve (FFR) is a critical physiological indicator for assessment of impaired blood flow caused by coronary artery stenosis. The wire-based invasive measurement of blood flow pressure gradient across stenosis is the gold standard for clinical measurement of FFR. However, it has the risk of vascular injury and requires the use of vasodilators, increasing the time and overall cost of interventional examination. Coronary imaging is playing an important role in clinical diagnosis of stenotic lesions, evaluation of severity of lesions, and planning of therapies. In recent years, the computation of FFR based on the physiological information of blood flow obtained from routinely collected coronary image data has become a research focus in this field. This technique reduces the cost of physiological assessment of coronary lesions and the use of pressure wires. It is beneficial to strengthen the physiological guidance in interventional therapy. In order to better understand this emerging technique, this paper highlights its implementation principle and diagnostic performance, analyzes practical problems and current challenges in clinical applications, and discusses possible future development.

Quantification and limitation of CT coronary angiography using 128-slice dual-source CT at high heart rate: A simulation study / 西安交通大学学报(医学版)

Objective: To simulate the systolic imaging of high-pitch scan for CT coronary angiography in order to evaluate and analyze the distribution features of systolic triggered temporal window (STTW) for high-pitch scan at high heart rate (HR). Methods: Sixty-two consecutive patients were enrolled in our study. Retrospective electrocardiography (ECG) gating low-pitch scan with full cardiac cycle reconstruction was used for all the patients. The reconstruction thickness and gap were 0.75mm and 13.75mm, respectively. The data from 0 ms to 700 ms after R wave was reconstructed with every 10 ms. The STTW would be evaluated from 0 ms to 400 ms. Results: The mean HR was (75.52±8.73)times/min. The STTWwidth (STTWw) was (120.16±75.13)ms for absolute phase and (14.70±8.74)% for relative phase. The STTWcenter (STTWc) was (148.31±51.79)ms for absolute phase and (18.24±5.60)% for relative phase. There was a negative correlation between HR and relative STTWc (r=-0.306, P=0.016). Cut-off value of image assessment was 86bpm (AUC=0.933, P=0.038). Conclusion: Our study described the features of STTW, explained the feasibility of routine high-pitch CTCA with end systolic acquisition at high HR, and revealed the values and limitations of high-pitch scan at high HR.

Comparison of radionuclide myocardial perfusion imaging and multilayer spiral CT in the diagnosis of 36 patients with coronary artery disease / 中国基层医药

Objective To compare the clinical effect of radionuclide myocardial perfusion imaging(SPECT)and multilayer spiral CT coronary artery imaging(MSCT) in the diagnosis of coronsry artery disease(CHD).Methods The clinical data of 36 patients suspected with CHD and routine inspection of SPECT and MSCT were retrospectively analyzed.The diagnostic effects of two methods were compared.Results The sensitivity,specificity and the rate of accuracy of SPECT was 89.47％,94.12％,and 91.67％,respectively,while the sensitivity,specificity and the rate of accuracy of MSCT was 84.21％,94.12％,and 88.89％,respectively.There were no obvious difference in two groups (x2 =1.265,1.668,2.005,1.526,1.889,all P ＞ 0.05 ).Conclusion There was a high degree consistency on the diagnosis of CHD between SPECT and MSCT.In the application,combined with the two methods could improve the diagnosis of CHD.

Influence of individualized nursing intervention on success rate of holding breathing in patients undergoing dual-source CT imaging / 中国实用护理杂志

ObjectiveTo discuss the infiuence of personalized nursing intervention on success rate of holding breathing in patients undergoing dual-source CT imaging.Methods167 cases of patients were randomly divided into the observation group(100 cases)and the control group(67 cases). The control group implemented routine care, on the basis of routine care, the observation group was given pertinent and individualized nursing intervemion according to the factors causing failure of holding breathing, including better psychological counseling for patients, the right guidance, to alleviate symptoms, to improve comfort degree, to give clinical evaluation after inspection, et al.ResultsThe success rate of holding breathing in the observation group and the control group was 99.0％ and 88.1％, the observation group was significantly higher than the control group.ConclusionsHealth education for patients, attention to patients' illness, mental state, cognitive and behavioral changes in a timely manner to give individualized nursing intervention and seriously check the implementation of results in patients, can effectively improve the success rate of holding breathing in patients undergoing dual-source CT coronary angiography.

3D Whole-Heart Coronary MR Angiography at 1.5T in Healthy Volunteers: Comparison between Unenhanced SSFP and Gd-Enhanced FLASH Sequences

OBJECTIVE: To validate the optimal cardiac phase and appropriate acquisition window for three-dimensional (3D) whole-heart coronary magnetic resonance angiography (MRA) with a steady-state free precession (SSFP) sequence, and to compare image quality between SSFP and Gd-enhanced fast low-angle shot (FLASH) MR techniques at 1.5 Tesla (T). MATERIALS AND METHODS: Thirty healthy volunteers (M:F = 25:5; mean age, 35 years; range, 24-54 years) underwent a coronary MRA at 1.5T. 3D whole-heart coronary MRA with an SSFP was performed at three different times: 1) at end-systole with a narrow (120-msec) acquisition window (ESN), 2) mid-diastole with narrow acquisition (MDN); and 3) mid-diastole with wide (170-msec) acquisition (MDW). All volunteers underwent a contrast enhanced coronary MRA after undergoing an unenhanced 3D true fast imaging with steady-state precession (FISP) MRA three times. A contrast enhanced coronary MRA with FLASH was performed during MDN. Visibility of the coronary artery and image quality were evaluated for 11 segments, as suggested by the American Heart Association. Image quality was scored by a five-point scale (1 = not visible to 5 = excellent). The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were evaluated at the proximal coronary arteries. RESULTS: The SSFP sequence rendered higher visibility coronary segments, higher image quality, as well as higher SNR and CNR than the Gd-enhanced FLASH technique at 1.5T (p < 0.05). The visibility of coronary segments, image quality, SNR and CNR in the ESN, MDN and MDW with SSFP sequence did not differ significantly. CONCLUSION: An SSFP sequence provides an excellent method for the 3D whole-heart coronary MRA at 1.5T. Contrast enhanced coronary MRA using the FLASH sequence does not help improve the visibility of coronary segments, image quality, SNR or CNR on the 3D whole-heart coronary MRA.

Method for Automatic Tube Current Selection for Obtaining a Consistent Image Quality and Dose Optimization in a Cardiac Multidetector CT

OBJECTIVE: To evaluate a quantitative method for individually adjusting the tube current to obtain images with consistent noise in electrocardiogram (ECG)-gated CT cardiac scans. MATERIALS AND METHODS: The image noise from timing bolus and cardiac CT scans of 80 patients (Group A) who underwent a 64-row multidetector (MD) CT cardiac examination with patient-independent scan parameters were analyzed. A formula was established using the noise correlation between the timing bolus and cardiac scans. This formula was used to predict the required tube current to obtain the desired cardiac CT image noise based on the timing bolus noise measurement. Subsequently, 80 additional cardiac patients (Group B) were scanned with individually adjusted tube currents using an established formula to evaluate its ability to obtain accurate and consistent image noise across the patient population. Image quality was evaluated using score scale of 1 to 5 with a score of 3 or higher being clinically acceptable. RESULTS: Using the formula, we obtained an average CT image noise of 28.55 Hounsfield unit (HU), with a standard deviation of only 1.7 HU, as opposed to a target value of 28 HU. Image quality scores were 4.03 and 4.27 for images in Groups A and B, respectively, and there was no statistical difference between the image quality scores between the two groups. However, the average CT dose index (CTDIvol) was 30% lower for Group B. CONCLUSION: Adjusting the tube current based on timing bolus scans may provide a consistent image quality and dose optimization for cardiac patients of various body mass index values.

Elective vs non-elective radial artery grafts: comparing midterm results through 64-Slice computed tomography

BACKGROUND: Left internal thoracic artery to left anterior descending artery (LITA-LADA) grafting has become a fundamental part of the coronary artery bypass graft procedure (CABG). This grafting in turn has led to an increased use of other arterial conduits, of which the radial artery (RA) is most popular. Whether RA grafting can be used in the emergency patient is controversial. METHODS: 47 patients with critical stenosis (>70 percent) in all target vessels underwent CABG with LITA and RA grafts from 1996 to 2003. Patients were divided into elective (23 patients) and non-elective groups (24 patients) with LITA and RA grafts per patient being similar in both groups. Of these 47 patients, 5 died from non-cardiac complications and 12 were unavailable. Thus, 30 patients (71 percent of survivors) were studied by multidetector computed tomography. A total of 36 LITA and 64 RA grafts were studied. RESULTS: The RA patency rate for elective and non-elective grafts were 82 percent (31/38) and 85 percent (22/26), respectively (p=0.75). The RA had a similar patency rate for all target vessels ranging from 73 percent to 100 percent. Only one patient had a redo CABG and 29 (97 percent) are free from angina or re-intervention. LITA-LADA had a 92 percent (11/12) and 100 percent (10/10) patency rate for elective and non-elective groups, respectively (p=0.37). The sequential LITA-diagonal-LADA in the elective group had a 50 percent (03/06) patency rate, which was significantly lower than the 100 percent (08/08) patency rate of the non-elective group (p=0.02). CONCLUSION: Radial Artery grafts can be used in both elective and non-elective patients with excellent results.

INTRODUÇÃO: A anastomose da artéria torácica interna esquerda com a artéria descendente anterior (ATIE-DA) se tornou parte fundamental da cirurgia de revascularização do miocárdio (RM). Esta técnica levou ao aumento de utilização de outros enxertos arteriais, entre os quais, a artéria radial (AR) é muito usasa. Na literatura há controvérsia se a AR pode ser usada em pacientes em RM de emergência. MÉTODOS: 47 pacientes com lesões críticas (>70 por cento) em todas as artérias alvo foram submetidos à RM com ATIE e a AR entre 1996 e 2003. Os pacientes foram agrupados em eletivos (23 pacientes) e não eletivos (24 pacientes) sendo similares para número de enxertos de ATIE e AR por paciente. Dos 47 pacientes, 5 morreram de complicações não cardíacas e 12 não estavam disponíveis. Portanto, 30 pacientes (71 por cento dos sobreviventes) foram estudados com tomografia computadorizada. Um total de 36 ATIE e 64 AR foram analisadas. RESULTADOS: a perviabilidade da AR nos grupos eletivo e não eletivo foram respectivamente 82 por cento (31/38) e 85 por cento (22/26) (p=0,75). A AR teve perviabilidade semelhante para todas as artérias alvo variando de 73 por cento a 100 por cento. Apenas um paciente foi submetido à nova RM e 29 (97 por cento) estão livres de angina ou nova re-intervenção. ATIE-DA teve perviabilidade de 92 por cento (11/12) e 100 por cento (10/10) respectivamente nos grupos eletivo e não-eletivo (p=0,37). ATIE-Diagonal-DA seqüencial obteve perviabilidade de 50 por cento (03/06) no grupo eletivo que foi significativamente menor que a perviabilidade de 100 por cento (08/08) do não-eletivo (p=0,02). CONCLUSÃO: A AR pode ser utilizada nos pacientes eletivos e não eletivos com excelentes resultados.