Application Progress of Arterial Spin Labeling Magnetic Resonance Imaging in Renal Perfusion Analysis / 中国医学科学院学报

Arterial spin labeling is a noninvasive,quantitative method for perfusion imaging,which does not need any contrast media.This technique has been used in the renal perfusion analysis.In this article,we briefly introduced this technique and summarized its application in healthy volunteers,acute kidney injury,chronic kidney diseases,renovascular diseases,renal tumors,and renal transplantation.

Myocardial Coverage and Radiation Dose in Dynamic Myocardial Perfusion Imaging Using Third-Generation Dual-Source CT

Lung cavities in chronic thromboembolic pulmonary hypertension

OBJECTIVES: Chronic thromboembolic pulmonary hypertension (CTEPH) is a unique form of pulmonary hypertension (PH) that arises from obstruction of the pulmonary vessels by recanalized thromboembolic material. CTEPH has a wide range of radiologic presentations. Commonly, it presents as main pulmonary artery enlargement, peripheral vascular obstructions, bronchial artery dilations, and mosaic attenuation patterns. Nevertheless, other uncommon presentations have been described, such as lung cavities. These lesions may be solely related to chronic lung parenchyma ischemia but may also be a consequence of concomitant chronic infectious conditions. The objective of this study was to evaluate the different etiologies that cause lung cavities in CTEPH patients. METHODS: A retrospective data analysis of the medical records of CTEPH patients in a single reference PH center that contained or mentioned lung cavities was conducted between 2013 and 2016. RESULTS: Seven CTEPH patients with lung cavities were identified. The cavities had different sizes, locations, and wall thicknesses. In two patients, the cavities were attributed to pulmonary infarction; in 5 patients, an infectious etiology was identified. CONCLUSION: Despite the possibility of being solely associated with chronic lung parenchyma ischemia, most cases of lung cavities in CTEPH patients were associated with chronic granulomatous diseases, reinforcing the need for active investigation of infectious agents in this setting.

Role of low dose 256-slice CT perfusion imaging in predicting mediastinal lymph node metastasis of lung cancer

SUMMARY OBJECTIVE: CT perfusion (CTP) is an imaging technique that can be used to evaluate the changes in the microcirculation of tumor tissues. Our study aimed to investigate the role of CTP in predicting mediastinal lymph node metastasis. METHODS: Clinical data of 58 patients who received surgical resection of lung cancer and lymph node dissection in our hospital from June 2012 to December 2014 were collected. Patients were divided into a positive lymph node metastasis group and a negative lymph node metastasis group. Parameters of CTP, including peak enhancement intensity (PEI), perfusion value (PV), as well as blood volume (BV), were compared between the two groups. The receiver-operating characteristic (ROC) curve was used to predict mediastinal lymph node metastasis. RESULTS: The PV of the positive lymph node metastasis group was significantly higher than that of the negative group (p < 0.001). The ROC curve analysis showed that PV can be used as an index to predict mediastinal lymph node metastasis of lung cancer. The sensitivity and specificity of a PV greater than 7.5ml·min-1·ml-1 in predicting lymph node metastasis of lung cancer were 78.3 % and 91.4 %, respectively. CONCLUSION: The PV of low dose CT perfusion can be used as an index for predicting mediastinal lymph node metastasis of lung cancer.

RESUMO OBJETIVOS: A perfusão por TC objetiva (CTP) é uma técnica de imagem que pode ser usada para avaliar as alterações na microcirculação de tecidos tumorais. Nosso estudo teve como objetivo investigar o papel da CTP na predição de metástases em linfonodos mediastinais. MÉTODOS: Dados clínicos de 58 pacientes que receberam ressecção cirúrgica de câncer de pulmão e dissecção de linfonodos em nosso hospital de junho de 2012 a dezembro de 2014 foram coletados. Os pacientes foram divididos em grupo positivo para metástase linfonodal e grupo negativo para metástase linfonodal. Parâmetros de CTP incluindo pico de intensidade de realce (PEI) e valor de perfusão (PV), bem como volume de sangue (BV), foram comparados entre os dois grupos. A curva característica de operação do receptor (ROC) foi usada para predizer metástase linfonodal mediastinal. RESULTADOS: PV do grupo de linfonodos metastáticos positivos foi significativamente maior do que o grupo negativo de linfonodos metastáticos (p<0,001). A análise da curva ROC mostrou que a PV pode ser usada como um índice para predizer a metástase linfonodal mediastinal do câncer de pulmão. A sensibilidade e a especificidade da VP maior que 7,5ml · min-1 · ml-1 na predição de metástase linfonodal de câncer de pulmão foram de 78,3% e 91,4%, respectivamente. CONCLUSÃO: A VP de perfusão por TC de baixa dose pode ser usada como um índice para a predição de metástase linfonodal mediastinal de câncer de pulmão.

Dynamic Contrast-Enhanced Ultrasound of Gastric Cancer: Correlation with Perfusion CT and Histopathology

OBJECTIVE: To assess the relationship between contrast-enhanced ultrasound (CEUS) parameters and perfusion CT (PCT) parameters of gastric cancers and their correlation with histologic features. MATERIALS AND METHODS: This prospective study was approved by our Institutional Review Board. We included 43 patients with pathologically-proven gastric cancers undergoing CEUS using SonoVue® (Bracco) and PCT on the same day. Correlation between the CEUS parameters (peak intensity [PI], area under the curve [AUC], rise time [RT] from 10% to 90% of PI, time to peak [TTPUS], and mean transit time [MTTUS]) and PCT parameters (blood flow, blood volume, TTPCT, MTTCT, and permeability surface product) of gastric cancers were analyzed using Spearman's rank correlation test. In cases of surgical resection, the CEUS and PCT parameters were compared according to histologic features using Mann-Whitney test. RESULTS: CEUS studies were of diagnostic quality in 88.4% (38/43) of patients. Among the CEUS parameters of gastric cancers, RT and TTPUS showed significant positive correlations with TTPCT (rho = 0.327 and 0.374, p = 0.045 and 0.021, respectively); PI and AUC were significantly higher in well-differentiated or moderately-differentiated tumors (n = 4) than poorly-differentiated tumors (n = 18) (p = 0.026 and 0.033, respectively), whereas MTTCT showed significant differences according to histologic types (poorly cohesive carcinoma [PCC] vs. non-PCC), T-staging (≤ T2 vs. ≥ T3), N-staging (N0 vs. N-positive), and epidermal growth factor receptor expression (≤ faint vs. ≥ moderate staining) (p values < 0.05). CONCLUSION: In patients with gastric cancers, CEUS is technically feasible for the quantification of tumor perfusion and may provide correlative and complementary information to that of PCT, which may allow prediction of histologic features.

Evaluation of total liver perfusion imaging of CT for efficacy of transcatheter arterial chemoembolization combined with apatinib on rabbit VX2 liver tumors / 中南大学学报(医学版)

To investigate the value of the total liver CT perfusion imaging in the evaluation of rabbit VX2 liver tumors treated with TACE and apatinib.
 Methods: Thirty-six rabbit VX2 liver cancer models were established and randomly divided into 4 groups. Group A: simple TACE group; Group B: simple oral administration of apatinib mesylate; Group C: TACE + oral apatinib mesylate; Group D: control group, administration of saline. CT perfusion imaging (CTPI) was performed before treatment and on the 7 and 14 days after the treatment to acquire perfusion parameters including blood flow (BF), blood volume (BV), MTT (mean transit time), surface permeability (PS), and hepatic artery fraction (HAF). One tumor rabbit was sacrificed in each group after the first perfusion scan, and the remaining tumor rabbits were sacrificed after the last perfusion scan on the 14th day of the treatment. The borders of the tumors were stained immunohistochemically, and microvascular density (MVD) was measured by anti-CD34. The differences of perfusion parameters were compared to evaluate the liver hemodynamic changes, and statistical repeated measurement variance analysist correlation analysis were performed.
 Results: There were no significant differences in CTPI parameters of BF, BV, MTT, HAF and PS between the 4 groups before treatment (P>0.05). After the treatment, HB, HAF and PS were decreased significantly in Group A, B, and C and slightly increased in the Group D. The value of MVD after 14 d treatment was 80.1±16.4 in Group A, 50.2±11.2 in Group B, 27.4±9.7 in Group C, 68.7±12.7 in Group D, respectively. The value of MVD in the Group C were significantly lower than that in Group A, B, and D. It showed positive correlation between BF, HAF, PS and MVD in Group B, C, and D, and there was no significant correlation between BV, MTT and MVD. It showed no significant correlation between MVD and each CTPI parameter in Group A.
 Conclusion: Total liver CT perfusion can quantitatively evaluate the blood perfusion information of rabbit liver VX2 tumor after TACE. TACE combined with oral apatinib can effectively inhibit tumor growth and improve the therapeutic effect of VX2 tumor.

Clinical Applications of Wide-Detector CT Scanners for Cardiothoracic Imaging: An Update

Technical developments in multidetector computed tomography (CT) have increased the number of detector rows on the z-axis, and 16-cm wide-area-coverage CT scanners have enabled volumetric scanning of the entire heart. Beyond coronary arterial imaging, such innovations offer several advantages during clinical imaging in the cardiothoracic area. The wide-detector CT scanner markedly reduces the image acquisition time to less than 1 second for coronary CT angiography, thereby decreasing the volume of contrast material and radiation dose required for the examination. It also eliminates stair-step artifacts, allowing robust improvements in myocardial function and perfusion imaging. Additionally, new imaging techniques for the cardiothoracic area, including subtraction imaging and free-breathing scans, have been developed and further improved by using the wide-detector CT scanner. This article investigates the technical developments in wide-detector CT scanners, summarizes their clinical applications in the cardiothoracic area, and provides a review of the recent literature.

Noninvasive Biomarker for Predicting Treatment Response to Concurrent Chemoradiotherapy in Patients with Hepatocellular Carcinoma

PURPOSE: To investigate noninvasive biomarkers for predicting treatment response in patients with locally advanced HCC who underwent concurrent chemoradiotherapy (CCRTx).MATERIALS AND METHODS: Thirty patients (55.5 ± 10.2 years old, M:F = 24:6) who underwent CCRTx due to advanced HCC were enrolled. Contrast-enhanced US (CEUS) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) were obtained before and immediately after CCRTx. The third CEUS was obtained at one month after CCRTx was completed. Response was assessed at three months after CCRTx based on RECIST 1.1. Quantitative imaging biomarkers measured with CEUS and MRI were compared between groups. A cutoff value was calculated with ROC analysis. Overall survival (OS) was compared by the Breslow method.RESULTS: Twenty-five patients were categorized into the non-progression group and five patients were categorized into the progression group. Peak enhancement of the first CEUS before CCRTx (PE1) was significantly lower in the non-progression group (median, 18.6%; IQR, 20.9%) than that in the progression group (median, 59.1%; IQR, 13.5%; P = 0.002). There was no significant difference in other quantitative biomarkers between the two groups. On ROC analysis, with a cutoff value of 42.6% in PE1, the non-progression group was diagnosed with a sensitivity of 90.9% and a specificity of 100%. OS was also significantly longer in patients with PE1 < 42.6% (P = 0.014).CONCLUSION: Early treatment response and OS could be predicted by PE on CEUS before CCRTx in patients with HCC.

Dynamic Susceptibility Contrast (DSC) Perfusion MR in the Prediction of Long-Term Survival of Glioblastomas (GBM): Correlation with MGMT Promoter Methylation and 1p/19q Deletions

PURPOSE: To investigate the surgical, perfusion, and molecular characteristics of glioblastomas which influence long-term survival after treatment, and to explore the association between MR perfusion parameters and the presence of MGMT methylation and 1p/19q deletions. MATERIALS AND METHODS: This retrospective study was approved by our institutional review board. A total 43 patients were included, all with pathologic diagnosis of glioblastoma with known MGMT methylation and 1p/19q deletion statuses. We divided these patients into long-term (≥ 60 months, n = 7) and short-term (< 60 months, n = 36) survivors, then compared surgical extent, molecular status, and rCBV parameters between the two groups using Fisher's exact test or Mann-Whitney test. The rCBV parameters were analyzed according to the presence of MGMT methylation and 1p/19q deletions. We investigated the relationship between the mean rCBV and overall survival using linear correlation. Multivariable linear regression was performed in order to find the variables related to overall survival. RESULTS: Long-term survivors (100% [7 of 7]) demonstrated a greater percentage of gross total or near total resection than short-term survivors (54.5% [18 of 33]). A higher prevalence of 1p/19q deletions was also noted among the long-term survivors (42.9% [3 of 7]) than the short-term survivors (0.0% [0 of 36]). The rCBV parameters did not differ between the long-term and short-term survivors. The rCBV values were marginally lower in patients with MGMT methylation and 1p/19q deletions. Despite no correlation found between overall survival and rCBV in the whole group, the short-term survivor group showed negative correlation (R2 = 0.181, P = 0.025). Multivariable linear regression revealed that surgical extent and 1p/19q deletions, but not rCBV values, were associated with prolonged overall survival. CONCLUSION: While preoperative rCBV and 1p/19q deletion status are related to each other, only surgical extent and the presence of 1p/19q deletion in GBM patients may predict long-term survival.

Postoperative Transient Neurologic Dysfunction: A Proposal for Pathophysiology

BACKGROUND AND PURPOSE: Sudden neurological deterioration which cannot be explained by structural change, ischemia or seizure is often observed among neurosurgical patients. We aimed to provide new insight into the pathophysiology of postoperative transient neurologic dysfunction. METHODS: We describe prolonged but fully reversible focal neurologic dysfunction of unknown origin based on the initial evaluation in 8 patients who had received encephalo-duro-arterio-synangiosis for moyamoya disease. We performed brain imaging, including diffusion weighted imaging and perfusion magnetic resonance imaging or single photon emission computed tomography, and electroencephalography (EEG) during the episodes and after resolution of the symptoms. RESULTS: The symptoms consisted of dysarthria, hemiparesis, or hemiparesthesia of limbs contralateral to the operated side. These symptoms developed between 12 hours and 8 days after surgery and lasted between 12 hours and 17 days. Structural imaging did not show any significant interval change compared with the immediate postoperative images. Perfusion imaging showed increased cerebral blood flow in the symptomatic hemisphere. EEG revealed low amplitude arrhythmic slowing in the corresponding hemisphere. Follow-up imaging and EEG after recovery did not show any abnormalities. CONCLUSIONS: Transient neurologic dysfunction can occur during the postoperative period of brain surgery. Although this may last more than usual transient ischemic attack or seizure, it eventually resolves regardless of treatment. Based on our observation, we propose that this is the manifestation of the transient cortical depression triggered by mechanical stimulation, analogous to migraine aura associated with cortical spreading depression.

Normal Magnetic Resonance Perfusion Imaging and Atypical Posterior Reversible Encephalopathy Syndrome in Chronic Kidney Disease

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) is classically characterized by symmetric vasogenic edema in the parietooccipital areas, but may occur at other sites with varying imaging appearances. CASE REPORT: A 55-year old female with chronic kidney disease (CKD) was admitted to the emergency room, presenting with nausea, vomiting and seizure. The initial blood pressure was 145/90 mmHg. Fluid attenuated inversion recovery demonstrated diffuse vasogenic edema in the bilateral cortical and subcortical white matters involving the frontal lobes. Perfusion magnetic resonance imaging (MRP) showed no hyper- or hypoperfusion at blood pressure levels of 140/50 mmHg. A follow-up magnetic resonance imaging at 3 weeks later demonstrated complete resolution of previous lesions. CONCLUSIONS: Earlier reports have demonstrated that PRES can occur in cases of atypical distributions, and features of imaging findings and normotensive settings. It is important to note that PRES is a dynamic process. As a result, we suggest that MRP must be considered in the appropriate temporal framework, to avoid misinterpretation of the other diseases, especially in CKD patients.

Comparison of Two Different Segmentation Methods on Planar Lung Perfusion Scan with Reference to Quantitative Value on SPECT/CT / 대한핵의학회잡지

PURPOSE: Until now, there was no single standardized regional segmentation method of planar lung perfusion scan.We compared planar scan based two segmentation methods, which are frequently used in the Society of Nuclear Medicine, with reference to the lung perfusion single photon emission computed tomography (SPECT)/computed tomography (CT) derived values in lung cancer patients.METHODS: Fifty-five lung cancer patients (male:female, 37:18; age, 67.8 ± 10.7 years) were evaluated. The patients underwent planar scan and SPECT/CT after injection of technetium-99 m macroaggregated albumin (Tc-99 m-MAA). The % uptake and predicted postoperative percentage forced expiratory volume in 1 s (ppoFEV1%) derived from both posterior oblique (PO) and anterior posterior (AP) methods were compared with SPECT/CT derived parameters. Concordance analysis, paired comparison, reproducibility analysis and spearman correlation analysis were conducted.RESULTS: The % uptake derived from PO method showed higher concordance with SPECT/CT derived % uptake in every lobe compared to AP method. Both methods showed significantly different lobar distribution of%uptake compared to SPECT/CT. For the target region, ppoFEV1% measured from PO method showed higher concordance with SPECT/CT, but lower reproducibility compared to AP method. Preliminary data revealed that every method significantly correlated with actual postoperative FEV1%, with SPECT/CT showing the best correlation.CONCLUSIONS: The PO method derived values showed better concordance with SPECT/CT compared to the AP method. Both PO and AP methods showed significantly different lobar distribution compared to SPECT/CT. In clinical practice such difference according to different methods and lobes should be considered for more accurate postoperative lung function prediction.

Clinical utility of left ventricular ejection fraction reserve by stress thallium-201 myocardial gated single photon computed tomography among patients with and suspected coronary artery disease

BACKGROUND: Coronary microcirculation impairment with sequential decrease in cardiac function is reflected by abnormal left ventricular ejection fraction reserve (LVEFR),which precedes diagnostic evidence of myocardial insult. However, prognostic utility of LVEFR is less, if not least explored. The aim of this study was to evaluate the clinical utility of LVEFR in predicting major cardiac events (MACE) among patients with and suspected coronary artery disease (CAD).MATERIALS AND METHODS: A retrospective cohort study of 245 patients who underwent stress thallium-201 myocardial perfusion scan (MPS) was conducted. The patients were categorized as having normal or abnormal perfusion scan. Each group was subdivided into normal and abnormal LVEFR groups. All subjects were followed up for any major adverse cardiac events 36 months after MPS through review of hospital records.RESULTS: There was an overall increase in the likelihood of cardiac events with abnormal LVEFR (i.e., odds ratio of 2.99,p=CONCLUSION: Abnormal LVEFR can be used as an independent predictor of cardiac events which can be observed in subjects with normal and abnormal perfusion scans alike.

Clinical utility of left ventricular ejection fraction reserve by stress thallium-201 myocardial gated single photon computed tomography among patients with and suspected coronary artery disease

BACKGROUND: Coronary microcirculation impairment with sequential decrease in cardiac function is reflected by abnormal left ventricular ejection fraction reserve (LVEFR),which precedes diagnostic evidence of myocardial insult. However, prognostic utility of LVEFR is less, if not least explored. The aim of this study was to evaluate the clinical utility of LVEFR in predicting major cardiac events (MACE) among patients with and suspected coronary artery disease (CAD).MATERIALS AND METHODS: A retrospective cohort study of 245 patients who underwent stress thallium-201 myocardial perfusion scan (MPS) was conducted. The patients were categorized as having normal or abnormal perfusion scan. Each group was subdivided into normal and abnormal LVEFR groups. All subjects were followed up for any major adverse cardiac events 36 months after MPS through review of hospital records.RESULTS: There was an overall increase in the likelihood of cardiac events with abnormal LVEFR (i.e., odds ratio of 2.99,p=CONCLUSION: Abnormal LVEFR can be used as an independent predictor of cardiac events which can be observed in subjects with normal and abnormal perfusion scans alike.

Absorption mechanism of three curcumin constituents through in situ intestinal perfusion method

This study aimed to investigate the absorption mechanism of three curcumin constituents in rat small intestines. Self-emulsification was used to solubilize the three curcumin constituents, and the rat in situ intestinal perfusion method was used to study factors on drug absorption, including drug mass concentration, absorption site, and the different types and concentrations of absorption inhibitors. Within the scope of experimental concentrations, three curcumin constituents were absorbed in rat small intestines through the active transport mechanism.

Assessment of Cervical Cancer with a Parameter-Free Intravoxel Incoherent Motion Imaging Algorithm

OBJECTIVE: To evaluate the feasibility of a parameter-free intravoxel incoherent motion (IVIM) approach in cervical cancer, to assess the optimal b-value threshold, and to preliminarily examine differences in the derived perfusion and diffusion parameters for different histological cancer types. MATERIALS AND METHODS: After Institutional Review Board approval, 19 female patients (mean age, 54 years; age range, 37–78 years) gave consent and were enrolled in this prospective magnetic resonance imaging study. Clinical staging and biopsy results were obtained. Echo-planar diffusion weighted sequences at 13 b-values were acquired at 3 tesla field strength. Single-sliced region-of-interest IVIM analysis with adaptive b-value thresholds was applied to each tumor, yielding the optimal fit and the optimal parameters for pseudodiffusion (D*), perfusion fraction (F(p)) and diffusion coefficient (D). Monoexponential apparent diffusion coefficient (ADC) was calculated for comparison with D. RESULTS: Biopsy revealed squamous cell carcinoma in 10 patients and adenocarcinoma in 9. The b-value threshold (median [interquartile range]) depended on the histological type and was 35 (22.5–50) s/mm² in squamous cell carcinoma and 150 (100–150) s/mm² in adenocarcinoma (p < 0.05). Comparing squamous cell vs. adenocarcinoma, D* (45.1 [25.1–60.4] × 10⁻³ mm²/s vs. 12.4 [10.5–21.2] × 10⁻³ mm²/s) and F(p) (7.5% [7.0–9.0%] vs. 9.9% [9.0–11.4%]) differed significantly between the subtypes (p < 0.02), whereas D did not (0.89 [0.75–0.94] × 10⁻³ mm²/s vs. 0.90 [0.82–0.97] × 10⁻³ mm²/s, p = 0.27). The residuals did not differ (0.74 [0.60–0.92] vs. 0.94 [0.67–1.01], p = 0.32). The ADC systematically underestimated the magnitude of diffusion restriction compared to D (p < 0.001). CONCLUSION: The parameter-free IVIM approach is feasible in cervical cancer. The b-value threshold and perfusion-related parameters depend on the tumor histology type.

Advanced MRI for Pediatric Brain Tumors with Emphasis on Clinical Benefits

Conventional anatomic brain MRI is often limited in evaluating pediatric brain tumors, the most common solid tumors and a leading cause of death in children. Advanced brain MRI techniques have great potential to improve diagnostic performance in children with brain tumors and overcome diagnostic pitfalls resulting from diverse tumor pathologies as well as nonspecific or overlapped imaging findings. Advanced MRI techniques used for evaluating pediatric brain tumors include diffusion-weighted imaging, diffusion tensor imaging, functional MRI, perfusion imaging, spectroscopy, susceptibility-weighted imaging, and chemical exchange saturation transfer imaging. Because pediatric brain tumors differ from adult counterparts in various aspects, MRI protocols should be designed to achieve maximal clinical benefits in pediatric brain tumors. In this study, we review advanced MRI techniques and interpretation algorithms for pediatric brain tumors.

Using a Thermal Imaging Camera to Locate Perforators on the Lower Limb

Reconstruction of the lower limb presents a complex problem after skin cancer surgery, as proximity of skin and bone present vascular and technical challenges. Studies on vascular anatomy have confirmed that the vascular plane on the lower limb lies deep to the deep fascia. Yet, many flaps are routinely raised superficial to this plane and therefore flap failure rates in the lower limb are high. Fascio-cutaneous flaps based on perforators offer a better cosmetic alternative to skin grafts. In this paper, we detail use of a thermal imaging camera to identify perforator ‘compartments’ that can help in designing such flaps.