Repeatability of the "flash-replenishment" method in contrast-enhanced ultrasound for the quantitative assessment of hepatic microvascular perfusion

This study aimed to evaluate the feasibility and repeatability of the flash-replenishment method in contrast-enhanced ultrasound (CEUS) perfusion imaging and assess quantitatively microvascular perfusion in the liver. Twenty healthy New Zealand rabbits were submitted to CEUS perfusion imaging with continuous intravenous infusion. Using flash-replenishment kinetics, the dynamic process of depletion and refilling of microbubble contrast agent was recorded. The hepatic microvascular perfusion parameters were calculated, including region of interest, peak intensity (PI), area under the curve (AUC), and hepatic artery to vein transit time (HA-HVTT). A consistency test was performed for multiple measurements by the same operator and blind measurements by two different operators. The hepatic perfusion imaging of 3×108 bubbles/min had minimal error and the best imaging effect and repeatability. The variability of the perfusion parameter measured at 3 cm depth under the liver capsule was at a minimum with coefficient of variation of 3.9%. The interclass correlation coefficient (ICC) of measurements taken by the same operator was 0.985, (95% confidence interval, CI=0.927-0.998). Measurements taken by two operators had good consistency and reliability, with the ICC of 0.948 (95%CI=0.853-0.982). The PI and AUC of liver parenchyma after reperfusion were lower than before blocking; and HA-HVTT was significantly longer than before blocking (P<0.05). The flash-replenishment method in CEUS perfusion imaging showed good stability and repeatability, which provide a valuable experimental basis for the quantitative assessment of hepatic microvascular perfusion in clinical practice.

Discrimination between Metastatic and Non-metastatic Regional Lymph Nodes in Rectal Cancer Using Quantitative Dynamic Contrast-enhanced Parameters / 中山大学学报(医学科学版)

[Objective]To investigate the diagnostic value of quantitative perfusion parameters of dynamic contrast-enhanced im?aging for discriminating metastatic from non-metastatic regional lymph nodes in rectal cancer.[Methods]122 patients of our depart?ment were collected from 2015.01 to 2016.08, and 203 lymph nodes, including metastatic lymph nodes (MLNs, n=95) and non-meta?static lymph nodes (NMLNs, n=108), were analyzed. The short-axis diameter (S), long-axis diameter (L), short-to long-axis diameter ratio (S/L), volume transfer constant (Ktrans), rate constant (Kep) and extravascular extracellular space (EES) fractional volume (Ve) were compared between two groups respectively. Then using S=5 mm as a cutoff value, these parameters were compared between subgroups. Receive operating characteristic curve (ROC) was used to analyze the diagnostic efficiency and find the optimal cutoff values.[Re?sults]The metastatic group exhibited higher S and L, but lower S/L, Ktrans and Kep than the non-metastatic group (P<0.01). However, the Ve did not differ significantly between two groups (P=0.308). Optimal cutoff values [area under the curve (AUC), sensitivity, speci?ficity] of Ktrans for discriminate metastatic lymph nodes from non-metastatic were 0.088 min-1 (0.69, 58.3%, 78.9%). When S>/=5 mm, subgroup analysis revealed that Ktrans and Kep of MLNs were significant higher than those of NMLNs (P<0.001), but Ve was lower (P=0.039). Optimal cutoff values (AUC, sensitivity, specificity) of Ktrans were 0.088 min-1 (0.675, 57.1%, 77.9%). However, when S<5 mm, MLNs showed lower Ktrans than NMLNs (P=0.001), but there were no significantly statistic differences of Kep and Ve between these two groups (P>0.1). Optimal cutoff values (AUC, sensitivity, specificity) of Ktrans were 0.087 min-1 (0.732, 60.5%, 81.5%).[Conclusion]Ktrans can be used to discriminate regional MLNs from NMLNs in rectal cancer, especially when the short-axis diameter is less than 5 millimeters.

Quantitative perfusion parameters of dynamic contrast-enhanced magne-tic resonance imaging in patients with rectal cancer:estimation of the mi-crovascular perfusion and permeability / 中国病理生理杂志

AIM:To investigate the perfusion parameters using dynamic contrast-enhanced magnetic resonance imaging ( DCE-MRI) in rectal cancer patients so as to explore its potential value in estimating the microvascular condition including perfusion and permeability .METHODS:The data of 38 rectal cancer patients examined with DCE-MRI was ret-rospectively analyzed .The perfusion parameters of carcinoma and normal rectal wall in each case were calculated , inclu-ding volume transfer constant (Ktrans), rate constant of back flux (Kep), extravascular extracellular space fractional volume (Ve) and initial area under curve (iAUC).The mean values of tumor and normal rectal wall , mucinous and nonmucinous carcinoma, poorly and moderately-to-well differentiated carcinoma , case with or without lymph node metastasis were com-pared.RESULTS:All the parameters of rectal cancer were higher than normal rectal wall (P<0.01).No significant difference was found between poorly and moderately-to-well differentiated carcinoma in terms of K trans, Kep and Ve, neither was the case with or without lymph node metastasis .The cases with lymph node metastasis had lower iAUC than those with-out (P<0.05).CONCLUSION:Quantitative perfusion DCE-MRI answered the microvascular perfusion and permeability change of rectal cancer compared with normal rectal wall , besides it could be used to distinguish between mucinous and nonmucinous carcinoma , which demonstrated its value in the evaluation of rectal cancer .However , it should not be recom-mended to predict the degrees of tumor cell differentiation and lymph node metastasis just according to the perfusion param -eters.

N-Acetylcysteine Improves Pancreatic Microcirculation and Alleviates the Severity of Acute Necrotizing Pancreatitis

BACKGROUND/AIMS: To investigate the beneficial effect of N-Acetylcysteine (NAC) on pancreatic microvascular perfusion in acute necrotizing pancreatitis (ANP). METHODS: Fifty-four rats were divided into a control group, an ANP group and an NAC-treated group. The ANP model was established by a retrograde injection of 3% sodium taurocholate into the pancreatic duct. The NAC-treated group received an intravenous infusion of NAC just 2 hours before and 30 minutes after the induction of ANP. The pancreatic microvascular perfusion was measured with laser Doppler flowmetry and pancreatic samples were collected for histological examination. RESULTS: The microvascular perfusion in the NAC-treated group decreased slightly and exhibited a significant increase compared to the ANP group (p<0.01). A pathological examination revealed that edema and inflammatory infiltration decreased, and the hemorrhaging and necrosis of the pancreas were significantly reduced. CONCLUSIONS: NAC could improve pancreatic microvascular perfusion and alleviate the severity of sodium taurocholate-induced ANP, possibly representing a new therapeutic approach to prevent the progression of ANP.

La meta de la reperfusión en los síndromes isquémicos coronarios agudos con elevación del segmento ST. El gran paradigma: "Lo que hay más allá del flujo TIMI 3 epicárdico: El TIMI 4 miocárdico" / The target of reperfusion in ST - elevation acute coronary syndromes: The major paradigm: "beyond TIMI 3 flow: The TIMI 4 or myocardial tissue - level perfusion"

En el tratamiento de los Síndromes Coronarios Agudos con elevación del segmento ST se ha avanzado en la última década de manera favorable en relación a la terapia fibrinolítica (TF), en los procedimientos coronarios intervencionistas (PCI) y con la utilización concomitante de los inhibidores de los receptores plaquetarios IIb/IIIa (IRP). El interés actual en relación al objetivo ha alcanzar en la reperfusión del infarto agudo del miocardio (IAM) ha girado de la arteria responsable del infarto (ARI) a obtener perfusión microvascular-tisular óptima. Se ha puntualizado que el establecer la mejor permeabilidad de la ARI (TIMI 3E) no es sinónimo de que también se ha obtenido en el tejido miocárdico (TIMI 4 M). Sabemos que puede existir disfunción microvascular producto de la microembolización plaquetaria o la ocasionada por la propia reperfusión, misma que esta ligada a los mediadores inflamatorios lo que da origen al "fenómeno de no- flujo", anomalía todas que ocurren en un número no despreciable de enfermos a pesar de haberse obtenido TIMI 3E. Hoy día hay técnicas y tratamientos que van encaminados a identificar y resolver estas anomalías con el fin de mejorar la perfusión microvascular en el IAM. A pesar de existir progresos en las estrategias de reperfusión en el IAM particularmente con el empleo adjunto de IRP y con la TF y que se obtienen en la ARI flujos TIMI 3E en el 50-75% de las veces y con los PCI en el 90-95%, no se han alcanzado reducciones significativas en la mortalidad, mas sí en la frecuencia de la retrombosis de la ARI, de los stents, de reinfartos y en algunos sujetos se observa mejoría de la función ventricular. Por lo tanto, hoy día estamos conscientes de lo que representa obtener perfusión óptima microvascular en el escenario del IAM. El gran paradigma es saber por lo tanto que hay más allá del TIMI 3E y si se alcanzo o no flujo TIMI 4 o miocárdico.

Treatment for ST- elevation acute coronary syndromes (acute myocardial infarction: AMI) has advanced rapidly in the last decade with major improvements in early fibrinolytic therapy (FT), primary percutaneous interventions (PCI) with the aid of platelet glycoprotein IIb/IIIa inhibitors. Recent interest has shifted from infarct related artery (IRA) patency to microvascular perfusion in the evaluation of patients with AMI. It is well known that establishing epicardial patency after AMI (TIMI 3 E) is not synonymus with tissue-level perfusion (TIMI 4M). Microvascular dysfunction due to the roles of platelet and inflammatory mediators in the no-reflow phenomenon occurs in a substancial proportion of patients despite thrombolytic therapy or PCI procedures. Techniques are now available that measure real tissue-level perfusion and also therapy is directed to optimize myocardial perfusion in patients with AMI. Despite advances, contemporary FT strategies with the combination of platelet glycoprotein IIb/IIIa inhibitors restore normal coronary flow (TIMI 3) in the IRA in only 50-75% and PCI achieves TIMI 3 flow rates in 90-95%, but only with modest reductions in mortality, but with significant reductions in rethrombosis of the IRA or stents, reinfarctions and in some patients with benefits in ventricular dysfunction. Therefore moving beyond the importance of TIMI 3 flow, the TIMI 4 flow, or improving tissue-level perfusion in the setting of AMI seems to be the paradigm for the treatment of ST-elevation acute coronary syndromes.