Assessment of cerebrovascular reserve impairment using the breath-holding index in patients with leukoaraiosis

Many studies have demonstrated that leukoaraiosis is associated with impaired cerebrovascular reserve function. However, the definitive hemodynamic changes that occur in leukoaraiosis are not clear, and there are many controversies. This study aimed to investigate hemodynamic changes in symptomatic leukoaraiosis using transcranial Doppler ultrasonography and the breath-holding test in a Chinese Han population, from northern China. A total of 203 patients who were diagnosed with ischemic stroke or clinical chronic progressive ischemic symptoms were enrolled in this study, including 97 males and 106 females, with an age range of 43-93 years. The severity of leukoaraiosis was evaluated according to the Fazekas grading scale, and patients were divided into four groups accordingly. Grade 0 was no leukoaraiosis, and grades I, II, and III were mild, moderate, and severe leukoaraiosis, respectively, with 44, 79, 44, and 36 cases in each group. Transcranial Doppler ultrasonography and the breath-holding test were performed. The mean blood flow velocity of the bilateral middle cerebral artery was measured and the breath-holding index was calculated. The breath holding index was correlated with leukoaraiosis severity and cognitive impairment. Patients with a low breath holding index presented poor performance in the Montreal Cognitive Assessment (MoCA) and executive function tests. That is, the lower the breath holding index, the lower the scores for the MoCA and the higher for the trail-making test Parts A and B. These results indicate that the breath-holding index is a useful parameter for the evaluation of cerebrovascular reserve impairment in patients with leukoaraiosis. In addition, the breath-holding index can reflect cognitive dysfunction, providing a new insight into the pathophysiology of leukoaraiosis. This study was approved by the Ethics Committee of the Fifth Peoples Hospital of Shenyang, China (approval No. 20160301) and registered in the Chinese Clinical Trial Registry (registration number: ChiCTR1800014421).

Lesion discrimination with breath-hold hepatic diffusionweighted imaging:A meta-analysis

AIM:To investigate the diagnostic capability of breathhold diffusion-weighted imaging(DWI) for differentiation between malignant and benign hepatic lesions.METHODS:A total of 614 malignant liver lesions(132 hepatocellular carcinomas,468 metastases and 14 intrahepatic cholangiocarcinomas) and 291 benign liver lesions(102 hemangiomas,158 cysts,24 focal nodular hyperplasia,1 angiomyolipoma and 6 hepatic adenomas) were included from seven studies(eight sets of data).RESULTS:The pooled sensitivity and specificity of breath-hold DWI were 0.93 [95% confidence interval(CI):0.91-0.95] and 0.87(95%CI:0.83-0.91),respectively.The positive likelihood ratio and negative likelihood ratio were 7.28(95%CI:4.51-11.76) and 0.09(95%CI:0.05-0.17),respectively.The P value for χ2 heterogeneity for all pooled estimates was < 0.05.From the fitted summary receiver operating characteristic curve,the area under the curve and Q * index were 0.96 and 0.91,respectively.Publication bias was not present(t = 0.49,P = 0.64).The meta-regression analysis indicated that evaluated covariates including magnetic resonance imaging modality,echo time,mean age,maximum b factor,and number of b factors were not sources of heterogeneity(all P > 0.05).CONCLUSION:Breath-hold DWI is useful for differentiating between malignant and benign hepatic lesions.The diffusion characteristics of benign lesions that mimic malignant ones have rarely been investigated.

Comparisons of Image Quality and ADCs in Breath-Hold, Respiratory-Triggered and Free-Breathing DWI of Pancreas at 3-T

Objective: To compare image quality and apparent diffusion coefficients (ADC) of the normal pancreas parenchymas in breath-hold, respiratory-triggered and free-breathing diffusion weighted imaging (DWI) at 3.0-Tesla. Methods: DWI of the pancreas was performed at 3.0-Tesla in 21 healthy volunteers with breath-hold, respiratory-triggered and free-breathing using b-values of 0 and 500 s/mm2. For all three sequences, two readers assigned an image quality score to images at b0 and b500, and two independent readers measured ADCs for the head, body and tail of pancreas. Image quality scores and ADCs of pancreas in the three DWIs were compared. Results: For b0, image quality scores was not significantly different among the three sequences (p = 0.103). For b500, image quality score was significantly lower in free-breathing DWI than breath-hold or respiratory-triggered DWI (p = 0.000), and not significantly different between breath-hold and respiratory-triggered DWI (p = 0.212). Mean ADCs differed significantly among the anatomical regions with the lowest values measured in the pancreatic tail both at breath-hold and respiratory-triggered DWIs whereas no significant difference was found at free-breathing DWI. Conclusion: Breath-hold or respiratory-triggered technique provided DW images of pancreas with acceptable quality at 3.0-Tesla. Breath-hold is the preferred DWI technique for ADC measurements of pancreas.

A Half-Arc Multiple Deep-Inspiration Breath-Hold Volumetric Modulated Arc Therapy for a Lung Tumor with 10 MV Flattening-Filter-Free Beams and an Image Sensor Measuring a Distance Map to Thorax Surface: An Initial Clinical Experience

A technique for multiple deep-inspiration breath-hold (DIBH) volumetric modulated arc therapy (VMAT) for a lung tumor has been proposed with 10 MV flattening-filter-free beams and an image sensor measuring a distance map to thorax surface. Planning CT images were acquired under a DIBH condition and a clinical target volume (CTV) was contoured. This procedure was repeated five times and an internal target volume (ITV) among the multiple DIBHs was created by integrating the five CTVs. A planning target volume (PTV) was defined by adding an isotropic margin of 5 mm to the ITV. Immediately before treatment, a 30-second half-arc cone-beam computer tomography (CBCT) imaging was performed under another DIBH condition, and the couch was repositioned so that tumor may be located inside the PTV contours. An infrared distance measurement device having laser diodes and an image sensor was attached to the couch, and a distance map to the patient thorax surface was recorded as a reference during still another DIBH condition. A half-arc segmented VMAT beams with two beam interrupts were delivered to the patient under multiple DIBHs, where the delivery time of each of the three segmented beams was 30 seconds. During the beam delivery, the distance map was monitored in real time to confirm that the distance to the thorax surface remained unchanged. In-treatment CBCT images suggested that the tumor position at the time of tumor registration was accurately reproduced during the DIBH VMAT delivery.

Cognitive Functional Impairment and Hemodynamic Changes in Patients with Symptomatic Leukoaraiosis

Objective: The pathogenesis of leukoaraiosis is still unclear. Many studies have determined that changes in the hemodynamics associated with leukoaraiosis, impaired cerebrovascular reserve, and intracranial hypoperfusion can lead to various clinical manifestations such as motor or cognitive impairment. The purpose of this study was to investigate the relationship between cognitive functional changes and imaging characteristics in patients with symptomatic leukoaraiosis, and to observe the corresponding changes in hemodynamics. Methods: A total of 203 Han patients (aged 43 - 93 years) with symptomatic leukoaraiosis were included in this study. Head magnetic resonance imaging was semi-quantified according to the Fazekas grading standard. Then, each patient was evaluated in terms of cognitive (Montreal scale) and executive function (trail-making test A [TMTA] and TMTB). Specifically, the TMTA asks patients to connect points on a piece of paper numbered from 1 to 25 in order and the TMTB asks patients to arrange numbers and letters in alternating order. In the current work, revised versions of these tests used are to include numbers in square and circular shapes where the shapes needed to be arranged in alternating order. The time required to complete the TMTA and TMTB was recorded. The changes in the blood flow velocity of the middle cerebral artery were also observed using routine Transcranial Doppler ultrasound and the breath-holding test. The dynamic curves of blood flow velocity during the breath-holding test were examined. Results: The cognitive and executive functions of patients with leukoaraiosis are related to the classification of image-based disease characteristics. In this sense, the more serious the leukoaraiosis is, the larger the impairment of cognitive and executive function is. According to the breath-holding test, the peak pattern of the blood flow velocity in the middle cerebral artery was significantly different between the various grades of leukoaraiosis. The peak type of Fazekas grade 0 and I was in the same direction, while the peak type of Fazekas grade II and III was significantly opposed (both p Conclusions: The impairment of cognitive and executive functions in patients with leukoaraiosis correlates with the severity of image-based disease manifestations, which are generally depicted as intracranial hypoperfusion.

Usefulness of two-point Dixon fat-water separation technique in gadoxetic acid-enhanced liver magnetic resonance imaging

AIM:To compare differences between volumetric interpolated breath-hold examination(VIBE) using two-point Dixon fat-water separation(Dixon-VIBE) and chemically selective fat saturation(FS-VIBE) with magnetic resonance imaging examination.METHODS:Forty-nine patients were included, who were scanned with two VIBE sequences(Dixon-VIBE and FS-VIBE) in hepatobiliary phase after gadoxetic acid administration.Subjective evaluations including sharpness of tumor, sharpness of vessels, strength and homogeneity of fat suppression, and artifacts that were scored using a 4-point scale.The liver-to-lesion contrast was also calculated and compared.RESULTS:Dixon-VIBE with water reconstruction had significantly higher subjective scores than FS-VIBE in strength and homogeneity of fat suppression(< 0.0001) but lower scores in sharpness of tumor(P < 0.0001), sharpness of vessels(P = 0.0001), and artifacts(P = 0.034).The liver-to-lesion contrast on Dixon-VIBE images was significantly lower than that on FS-VIBE(16.6% ± 9.4% vs 23.9% ± 12.1%, P = 0.0001).CONCLUSION:Dixon-VIBE provides stronger and more homogenous fat suppression than FS-VIBE, while has lower clarity of focal liver lesions in hepatobiliary phase after gadoxetic acid administration.

Development of forearm impedance plethysmography for the minimally invasive monitoring of cardiac pumping function

It is essential to continuously and non-invasively monitor the cardiac pumping function in clinical setting. Thus, the study aimed to explore a regional impedance phethysmographic method to assess the changes in stroke volume. To do this, we developed a plethysmographic device that was capable of delivering a single-frequency current with constant amplitude and of recording electrical impedance signals of biological tissue. The electrical impedance plethy- smographic waveform form the lower arm was measured with the impedance plethysmographic device, and simultaneously the end-systolic and end- diastolic volumes of the left ventricle were obtained with a two-dimension echocardiographic system in fourteen healthy subjects before and immediately after a thirty-second breath-hold maneuver. For the 14 subjects, a linear correlation coefficient of 0.79 (p < 0.001) was obtained between the changes in peak amplitude of the forearm impedance waveform and the changes in stroke volume before and just after the breath-hold test. In addition, the changes in the mean area under the impedance curve and the change in stroke volume were also correlated linearly (r = 0.71, p < 0.005). In summary, the forearm impedance plethysmography may be employed to evaluate the beat-to-beat alteration in cardiac stroke volume, suggesting its potential for long-term monitoring cardiac pumping performance.