Cyclic variation of myocardial integrated backscatter and myocardial wall thickness during percutaneous coronary angioplasty

Correlation between N-terminal pro B-natriuretic peptide and ultrasonic backscatter: implications for diastolic dysfunction in hypertension

OBJECTIVE

This study was designed to determine how N-terminal pro brain-natriuretic peptide (NT-proBNP) levels correlate with cyclic variation of integrated backscatter (CVIBS) as a reflection of abnormal diastolic function in hypertension.

PATIENTS

Forty essentially hypertensive patients were studied. CVIBS values were obtained from the septal wall in the parasternal long-axis view. Twelve had normal diastolic function, 18 had impaired relaxation, and 10 had pseudonormal pattern.

RESULTS

Patients with normal diastolic function had a mean NT-proBNP concentration of 34 +/- 17 pg/ml and a mean CVIBS value of 7.1 +/- 0.9 dB; those with impaired relaxation had a mean NT-proBNP concentration of 71 +/- 25 pg/ml and a mean CVIBS value of 6.7 +/- 1.1 dB. Patients with pseudonormal pattern had the highest NT proBNP levels (206 +/- 75 pg/ml) and lowest CVIBS values (5.7 +/- 0.9 dB). An NT-proBNP value of 62 pg/ml had a sensitivity of 83% and a specificity of 91%; a CVIBS value of 7.2 dB had a sensitivity of 83.3% and a specificity of 66.7% for detecting diastolic dysfunction. An NT-proBNP value of 120 pg/ml had a sensitivity of 76% and a specificity of 96%; a CVIBS value of 6.1 dB had a sensitivity of 87.5% and a specificity of 75% for detecting severe diastolic dysfunction. A close correlation was found between the NT-proBNP and CVIBS values (r: 0.54, P < 0.05).

CONCLUSION

Combinative use of NT-proBNP and CVIBS can detect the presence of diastolic abnormalities on echocardiography. A good correlation was found between the NT-proBNP and CVIBS values in detecting diastolic dysfunction in essentially hypertensive patients.

Relationship between myocardial ultrasonic integrated backscatter and mitochondria of the myocardium in dogs

OBJECTIVE

This study aimed to explore the relationship between integrated backscatter (IBS) and mitochondria in arrested myocardium.

METHODS

Twelve open-chest dogs were randomly divided into two groups: one group with cardiac arrest in systole and the other with cardiac arrest in diastole. IBS images at parasternal papillary muscle short-axis view were stored at different time frames (0, 30, and 60 min after cardiac arrest). The values of ultrasonic IBS were obtained using the acoustic densitometry technique. After ultrasound examination, tissue samples of corresponding times were harvested and observed under the transmission electron microscope. The microscopic images were analyzed using a computer imaging analysis system to obtain the stereological parameters of mitochondria. The correlation between IBS and the stereological parameters was analyzed.

RESULTS

After cardiac arrest, swollen mitochondria with electron-lucent matrix could be observed in some myofibers following the progression of time. The alteration of IBS correlated well with that of mitochondrial stereological parameters, such as volume density (Vv), surface density (Sv), average volume (v), average surface area (s), and specific surface (Rsv, ratio between surface and volume).

CONCLUSION

Mitochondria might be an important scatterer in the myocardium for IBS.

Ultrasound Tissue Characterization by Integrated Backscatter for Analyzing Fluorouracil Induced Myocardial Damage

BACKGROUND

5-Fluorouracil (5-FU) cardiotoxicity is a well-known clinical phenomenon whose pathophysiology remains controversial. Cyclic variation of integrated backscatter (CVIBS) assesses acoustic properties of myocardium that may reflect both contractility and structural changes. The aim of this study was to evaluate CVIBS alterations in cancer patients under high-dose leucovorin and infusional 5-FU (HDLV5FU) chemotherapy.

METHOD

We prospectively evaluated 37 cancer patients under HDLV5FU treatment. Transthoracic echocardiography and CVIBS were performed at the 0th, 48th hours, and on day 15 of the first cycle. The parasternal long-axis view was preferred to obtain the image of integrated backscatter and mainly two regions of interest--interventricular septum (IVS) and posterior wall (PW)--were used.

RESULTS

Clinical cardiotoxicity was observed in two patients. No significant differences were detected in pre- and posttreatment conventional echocardiography evaluations. However, both the IVS (9.3 +/- 1.0 to 8.1 +/- 1.2 dB, P < 0.001) and PW (9.1 +/- 0.7 to 7.8 +/- 0.9 dB, P < 0.001) CVIBS values significantly decreased in all patients. All values were returned to pretreatment levels (9.2 +/- 0.9 dB in the CVIBS-IVS and 8.9 +/- 0.6 dB in CVIBS-PW, respectively) on day 15 after the treatments.

CONCLUSION

This study suggests that HDLV5FU may cause acute transient alterations in CVIBS values in the absence of clinical symptoms and signs of cardiotoxicity. The clinical value of CVIBS should be further studied in patients receiving 5-FU-based therapy.