Multi-detector-row CT angiography of peripheral arteries

The development of multi-detector-row CT (MDCT), within recent years, dramatically improved image quality and expanded the applications for non-invasive CT angiography. Since the introduction of four-detector-row CT (4-DCT) systems in 1998, MDCT technology has spread rapidly and is now widely available. This technique already meets the requirements for many vascular applications with respect to acquisition speed, anatomical coverage and spatial resolution. The newest MDCT scanners offer the advantages of up to 16 detector rows and gantry rotation as fast as 500 msec, further expanding the possibilities for CT angiography. For the assessment of the aorta and the iliac vessels MDCT has already proven to be superior to single detector CT and comparable to conventional angiography. This article reviews the status of MDCT angiography, including technical aspects, reformation methods and limitations, and clinical applications at the current state of the art.     

Noninvasive assessment of the viscoelasticity of peripheral arteries

Currently used methods of examining the mechanical properties of blood vessel walls are either indirect or invasive, or measure vessel diameter and pressure waveforms at different sites. We developed a noninvasive technique to assess the mechanical properties and viscoelasticity of peripheral arteries. The pressure-strain elastic modulus (Ep) and the viscoelastic properties (energy dissipation ratio, EDR) of the common carotid artery (CCA), brachial artery (BA), radial artery (RA) and dorsalis pedis artery (DPA) were determined by means of palpating pressure and diameter distension waveforms extracted from high-resolution ultrasonography. The methodology was validated in vitro using an elastic tube phantom, as well as in vivo. In vivo study in 10 healthy volunteers (mean age 22 y) showed that the pressure-diameter curves were nonlinear, with an inflection at about 85–90 mmHg, and routed clockwise with slight hysteresis. The CCA (n = 5) had a mean diameter of 6.74 mm and the pulsatile diameter distension was 12.2%. The Ep calculated at the CCA was 0.44 × 10⁶ dyne/cm² with an EDR of 7.18%. The BA, RA and DPA (n = 10) had mean diameters of 3.91 mm, 2.21 mm and 2.12 mm; arterial strains of 4.60%, 4.25% and 8.91%; mean Ep of 1.39, 1.45, 0.90 × 10⁶ dyne/cm²; and mean EDRs of 6.34%, 6.15% and 5.60%, respectively. The method presented is relatively simple to implement clinically and has potential as a new diagnostic tool for detecting local vascular changes.     

Echographic patterns of malignant lymphoma

Contact B mode ultrasound was used to evaluate 53 patients with malignant lymphoma stages III and IV. The echographic characteristics of retroperitoneal involvement by these lesions were evaluated to establish diagnostic criteria. This method can be used also to evaluate regression of retroperitoneal tumor involvement of paravertebral or paraaortic lymph nodes during anticancer chemotherapy.     

外周动脉非增强MR血管成像的研究现状

开展外周动脉非增强MR血管成像对肾功能不全或其他原因不能使用MR对比剂的患者以及四肢远端的动脉成像具有重要临床意义。作者从如何消除静脉及其他软组织背景和如何获取稳定高信噪比动脉信号两个方面重点介绍了较早基于三维快速自旋回波的非增强外周动脉成像方法和近期发展基于三维平衡稳态自由进动和血流敏感散相脉冲序列血管成像技术的发展现状和临床应用潜力。     

MSCT肺动脉成像不同参数对周围肺动脉显示率的对比研究

目的：采用MSCT不同注射速率、对比剂浓度及准直评价周围肺动脉的显示。方法：收集我院2011年2—10月行胸部增强扫描并符合纳入标准的病例100例,分别按照对比剂浓度及注射速率分为A、B、C、D四组;不同准直即0.6 mm,1.5 mm分为D、E两组;统计学分析肺动脉干、左右肺动脉及4级肺动脉CT值和5、6肺动脉显示率;结果：5组肺动脉干、左右肺动脉及4级肺动脉CT值比较有差异（P<0.05）;4级肺动脉分支显示数目无统计学意义（P=0.19）;5级肺动脉显示率下叶区有统计学差异（P<0.05）;6级肺动脉显示率每个叶区均有统计学差异（P<0.05）;D组与E组比较5级肺动脉显示率无统计学意义（P=0.48）,6级肺动脉显示率有差异（P=0.00）。结论：采用0.6 mm准直,浓度350 mgI/mL,注射速率5 mL/s可以显著提高周围肺血管显示率。     

Echographic changes with placental ageing

After 36 weeks gestation the placenta has a distinct echographic appearance which is characterized by rounded transonic areas measuring 1.5 to 4.5 cm. in diameter. Anatomic and histologic study of seven placentas with this echographic appearance has snown no abnormalities or characteristic findings. The recognition of the mature placenta is of clinical use in the determination of dysmaturity and growth retardation, where a single fetal head measurement may be misleading. The changes in the internal consistency of the placenta are most easily identified with a real-time, water bath, linear scanner (Siemens Vidoson) but may also be seen with a compound contact scanner if non-storage recording is employed.     

Echographic characteristics of malignant lymph nodes

We retrospectively reviewed the sonograms of 42 sequential patients for whom there was sonographic evidence of malignant lymphadenopathy. Twenty-three patients were known to have lymphoma, whereas 19 patients had lymph nodes involved with metastases. Each case was categorized according to the sonographic “texture” of the masses and the extent of sound transmission. Sonolucent masses were observed in 83% of the lymphoma cases and in 53% of patients with soft-tissue tumors. Nonetheless, a mixture of patterns was observed in nearly one-third of the cases. In 5 lymphoma patients there were enlarged lymph nodes that had all of the echographic qualities of simple cysts. Aside from this pattern, no correlation could be made between sonographic pattern and histologic diagnosis.     

Evaluation of clinical results following laser recanalization of the peripheral arteries

As experience is gained with laser-assisted angioplasty and as long-term follow-up results become available, a realistic and objective view of its role in the treatment of patients with occlusive disease of arteries in the peripheral vascular tree is becoming available. Comparison with results of conventional treatment methods is warranted. Experience in treating patients with vascular lesions is helpful in patient selection, management during the procedure, and follow-up care. Evaluation of experience in 169 procedures, with a follow-up time of 1 month to 3 years indicates what direction evolving patency rates are taking.