Hemodynamic alterations in unilateral chronic middle cerebral artery stenosis patients and the effect of percutaneous transluminal angioplasty and stenting: a perfusion-computed tomography study.

BACKGROUND: The Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial indicated that most patients with symptomatic intracranial atherosclerosis are not good candidates for percutaneous transluminal angioplasty and stenting (PTAS) because of a higher complication risk than with conservative treatment. However, enrollment of SAMMPRIS patients was based on lesion severity only, without functional imaging. PURPOSE: To determine whether perfusion computed tomography (PCT) can effectively evaluate hemodynamic compromise in unilateral chronic middle cerebral artery stenosis and the alterations of hemodynamics after PTAS. MATERIAL AND METHODS: In this prospective study, 89 patients with unilateral middle cerebral artery (MCA) stenosis/occlusion were enrolled and classified into four groups according to the degree of stenosis. Cerebral hemodynamics was evaluated by measuring cerebral blood flow (CBF), cerebral blood volume (CBV), and time to peak (TTP) in the ipsilateral and contralateral hemispheres by PCT before and after intervention with PTAS. Differences in hemodynamic parameters before and after intervention were analyzed. RESULTS: Three different hemodynamic patterns were observed in these patients. Patients with severe MCA stenosis (70-99%) or MCA occlusion demonstrated a significant increase of ipsilateral CBV and TTP, indicating hemodynamic compromise. Ten severe stenosis patients with recurrent ischemic symptoms despite of maximal conservative therapy were selected for PTAS. PTAS induced a rapid recovery of cerebral hemodynamics (especially TTP) at 1 week post intervention. CONCLUSION: PCT appears to be a valuable noninvasive technique to evaluate hemodynamic compromise in unilateral chronic MCA stenosis and the improvements after PTAS.

Multi-modality imaging findings of splenic hamartoma: a report of nine cases and review of the literature.

PURPOSE: To investigate the presentation of splenic hamartomas (SHs) on ultrasonography (US), CT and MRI. METHODS: Nine patients (5 males and 4 females, mean age, 52.8 years) with pathologically proven SHs were included in this study. US, CT and MRI images were analyzed retrospectively, and imaging features were correlated with pathological findings. RESULTS: SHs appeared solitary lesion (n = 8) and multiple lesions (n = 1) in the present study. (1) In 8 cases of solitary lesion, the lesions appeared as solid nodules or masses with well-defined margins and varying echogenicity (hyperecho = 5, hypoecho = 2, strong echo = 1) on ultrasound. The lesions showed iso-attenuation (n = 3) or slightly hypo-attenuation (n = 4) on unenhanced CT, and calcification were revealed in 3 lesions. MRI showed isointensity (n = 3) or hypointensity (n = 2) on the T1-weighted image, and heterogeneous hypointensity (n = 2), slightly hyperintensity (n = 2) and hyperintensity (n = 1) on the T2-weighted image. The enhanced patterns of SHs showed mild diffuse heterogeneous enhancement (n = 6) and prominent enhancement (n = 1) during arterial phase and above 7 lesions were demonstrated progressive enhancement at delayed phase on enhanced CT. One lesion without any enhancement was revealed in another patient. (2) One case of multiple lesions included 1 cystic lesion with irregular calcification and 7 solid lesions with progressive enhancement on CT images. CONCLUSIONS: Combination of a variety of imaging modalities could more fully reflect the pathological characteristics and contribute to the diagnosis of SH.

Monitoring early response of lymph node metastases to radiotherapy in animal models: diffusion-weighted imaging vs. morphological MR imaging.

BACKGROUND: Diffusion-weighted imaging (DWI) offers a non-invasive technique that can reveal microscopic details about the architecture of both normal and anomalous tissues. Some studies have confirmed DWI can detect the early changes of tumors that have originated from various organs, even after treatment. PURPOSE: To compare the usefulness of apparent diffusion coefficient (ADC) and morphologic magnetic resonance (MR) imaging for monitoring the therapeutic response of metastatic disease in lymph nodes to radiotherapy. MATERIAL AND METHODS: Twenty-six rabbits (metastatic, n = 17; non-metastatic, n = 9) were divided into group A (metastatic, n = 10), group B (metastatic, n = 7) and group C (non-metastatic, n = 9). Groups A and C underwent irradiation, whereas group B was set as a reference. Standard MR imaging and DWI were performed before and 1, 3, and 7 days after radiotherapy for all rabbits. The lymph node volumes and ADCs were measured and evaluated with repeated measures ANOVA. The difference between group A and B was analyzed using Student's t-test. RESULTS: In all rabbits, a total of 35 lymph nodes were found, including 16 nodes in group A, 10 in group B and nine in group C. In group A, 3 and 7 days after therapy ADCs were significantly higher than pre-treatment and 1 day after therapy (P < 0.05). For groups A and B, a significant difference of ADCs was present 7 days after therapy. A significant difference of variation of ADCs among the three groups was also present (P < 0.001). CONCLUSION: DWI is superior to morphological MRI in monitoring early radiation response in animal models.

Telomerase activity (TMA) in tumour and peritumoural tissues in a rat liver cancer model.

PURPOSE: To study the levels of telomerase activity (TMA) in tumour and peritumoural tissues in a liver cancer model in rats, and to study the change in TMA expression over time. METHODS: Using the telomeric repeated amplification protocol (TRAP), TMA was measured in tumour tissue, peritumoural tissue and normal liver tissue of Walker-256 tumour-bearing rats at 4, 6 and 8 days after tumour implantation. RESULTS: TMA at day 4, 6 and 8 was 0.767+/-0.117, 0.768+/-0.118 and 0.774+/-0.111 in tumour tissue, 0.389+/-0.263, 0.492+/-0.253 and 0.584+/-0.239 in peritumoural tissue, and 0.231+/-0.022, 0.229+/-0.022 and 0.233+/-0.021 in normal liver tissue, respectively. TMA in tumour tissue was higher than that in peri-tumour and normal liver tissues at all time points of measurement (P < 0.05). The TMA levels in tumour tissue and normal liver tissue did not show any change over time. TMA level in the peritumoural tissue increased with time; TMA level in animals sacrificed at day 8 was higher than that seen in animals sacrificed at day 4 (P < 0.05). CONCLUSION: TMA in walker-256 tumour-bearing rats was higher than that in normal and peritumoural tissues. TMA level in the peritumoural tissue increased with time suggesting that TMA activation in peritumoural tissue may be an important factor promoting tumour growth.

[In vivo proton magnetic resonance spectroscopy of hepatocellular carcinoma and cholangiocarcinoma].

OBJECTIVE: To investigate the value of in vivo proton magnetic resonance spectroscopy (1H MRS) in the assessment of hepatocellular carcinoma (HCC) and cholangiocarcinoma. METHODS: 1H MRS was performed in normal volunteers and in patients with pathologically confirmed HCC and cholangiocarcinomas using a whole-body 1.5-T scanner. The choline-to-lipid ratios were measured by dividing the peak area of choline at 3.2 ppm and lipid at 1.3 ppm. RESULTS: The ratio of choline-to-lipid for normal liver, cholangiocarcinomas, and HCC were 0.07 +/- 0.04, 0.11 +/- 0.06, and 0.52 +/- 0.15, respectively. The ratio of choline-to-lipid was significantly higher in HCC compared than those in cholangiocarcinomas or normal livers (P < 0.05). However, it was not significantly different between cholangiocarcinomas and normal livers (P > 0.05). CONCLUSION: In vivo 1H MRS can reflect the pathological changes of HCC and cholangiocarcinomas at metabolic level and thus is useful in the diagnosis of these two cancers.

Visceral artery aneurysms: evaluation using 3D contrast-enhanced MR angiography.

OBJECTIVE: Visceral artery aneurysms are uncommon, but they are clinically important because of the high incidence of rupture and life-threatening hemorrhage. Visceral artery aneurysms in patients with vascular anatomic variations are extremely rare, but detecting these variations is significant in this setting to determine the best treatment strategy; therefore, a thorough assessment of the aneurysm and of the vascular anatomy before treatment is paramount. CONCLUSION: Three-dimensional contrast-enhanced MR angiography is a noninvasive technique for the diagnosis and display of visceral artery aneurysms. It can provide 3D anatomic information that is needed for surgery or embolization.

Cavernous transformation of the portal vein: three-dimensional dynamic contrast-enhanced MR angiography.

BACKGROUND: To investigate characteristic features of three-dimensional dynamic contrast-enhanced MR angiography (3D DCE-MRA) and validate its clinical significance for the diagnosis of cavernous transformation of the portal vein (CTPV). METHODS: 3D DCE-MRA, along with subsequent data processing using three-dimensional reconstruction, was performed in 33 CTPV patients. We observed 33 emboli in the portal vein, 29 in the left and/or right portal branches, 18 in the superior mesenteric vein, and nine emboli in the splenic vein. RESULTS: The main presentation of CTPV on 3D DCE-MRA was the replacement of the normal configuration of the portal vein by numerous distorted hepatopetal collateral vessels, the presence of arterio-portal venous shunts, and the appearance of hepatofugal collateral vessels in the abdominal cavity and wall. CONCLUSION: 3D DCE-MRA can be used to simultaneously characterize the portal system and collateral vessels, and can improve the diagnosis and clinical treatment of CTPV.

Simultaneous enantiomer determination of 20 (R)- and 20 (S)-ginsenoside-Rg2 in rat plasma after intravenous administration using HPLC method.

20 (R,S)-Ginsenoside-Rg2, an anti-shock agent, is prescribed as a racemate. To analyze simultaneously the enantiomers of 20 (R)-ginsenoside-Rg2 and 20 (S)-ginsenoside-Rg2 in plasma, a simple and reproducible high-performance liquid chromatographic (HPLC) method has been developed. The enantiomeric separation and determination were successfully achieved using a Diamonsil ODS C18 reversed-phase column (5 microm, 250 mm x 4.6 mm) with an RP18 (5 microm) guard column and a mobile phase of MeOH-aq. 4% H3PO4 (65:35, v/v, pH 5.1) with UV detection at 203 nm. Both enantiomers, 20 (R)-ginsenoside-Rg2 and 20 (S)-ginsenoside-Rg2, were well separated at 14.5 min and 13.6 min, respectively. The linear ranges of the standard curves were 2.0-250 microg/ml. The intra- and inter-day precision (R.S.D.) were

[Screening for consecutive patient population with suspected CAD by 64-slice CT coronary angiography].

OBJECTIVE: To evaluate the screening for consecutive patient population with suspected Coronary atherosclerotic heart disease (CAD) by noninvasive 64-slice computed tomographic coronary angiography. METHODS: 2082 consecutive symptomatic subjects (1218 males, 868 female, with, mean age of 58.2 years old) with suspected CAD underwent MSCT studies. And 218 patients underwent coronary angiography within 7 days. Invasive coronary angiography was taken as golden standard for calculations of diagnostic accuracy. RESULTS: Of 2082 subjects, 2063 (99.1%) were assessable, the mean examination duration was 4 minutes. Compared with CAG, the sensitivity of CTA to diagnose significant stenosis was 97.4%, specificity 90.1%, positive predictive value (PPV) 91.8% and negative predictive value (NPV) 96.8%. CONCLUSION: Sixty-four-MSCT is accurate, convenient, noninvasive, safe means to coronary angiography with economic benefit. Thus, it can be considered as a valuable noninvasive screening technique.

[Natural history of small hepatocellular carcinoma: studied by MRI].

OBJECTIVE: To study natural history of small hepatocellular carcinoma (sHCC) and value of MRI in this research. METHODS: From 1999 to 2002, serial MR imagings were performed in 192 patients with cirrhosis no less than twice in order to detect sHCC focus. Characteristic MRI findings of focus were analysed. Diameters of focus (D) were measured. Tumorigenesis detected time (T) was counted; T and D were analysed by statistics and tumor volume doubling time (T(d)) was calculated. RESULTS: Fifty-eight new tumor foci in 33 patients were found, including 31 foci in 23 patients developed on the basis of cirrhosis, with a 12.0% cumulative tumorigenic rate of three years. The tumorigenesis detected time (T) was 386.9 +/- 256.4 days and the maximum diameter (D) was 2.258 +/- 1.074 cm. T was statistical correlated with D(3) (P < 0.01) and regressive formulas were established: D(3) = -2.69 + 0.058T (P = 0.0007), D(3) = -72.13 + 16.04lnT (P = 0.0064). Tumor volume doubling time was 20 approximately 279 days (mean: 104 days). CONCLUSION: The percentage of tumorigenesis is high in patients with cirrhosis. Regular MRI examinations are necessary to detect sHCC early. The optimal interval time is 3 approximately 6 months.

Study of the analgesic activities, chronic toxicity and addictive potential of Jia-Yuan-Qing pill in rats.

Jia-Yuan-Qing pill (JYQP) composed of Porcellio laevis Latreille, Corydalis Rhizoma and Radix Cynanchi Paniculati at a ratio of 9:7:7 has been found to be an effective analgesic agent. The present study aimed to evaluate the safety, addictive potential and anti-cancer pain activity of JYQP in a rat model. During the 6-month chronic toxicity test, no significant changes in general behavior, defecation, postural abnormalities, dietary or water intake or blood biochemical parameters were observed in male and female rats. Although a high dose of JYQP (5 g/kg) caused swelling of the liver, spleen and kidney in male and female rats, no pathological changes were observed in all organs examined via hematoxylin and eosin staining. The analgesic effect of JYQP on bone cancer pain was successfully confirmed in a rat model of Walker 256 cell-induced bone cancer. In contrast to morphine, in a physical dependence test, JYQP produced no withdrawal symptoms following chronic administration. The data from this study provide experimental evidence supporting the clinical use of JYQP as an effective, safe and non-addictive agent for the treatment of bone cancer pain.

CT-guided percutaneous ethanol injection with disposable curved needle for treatment of malignant liver neoplasms and their metastases in retroperitoneal lymph nodes.

AIM: To explore the feasibility of computed tomography (CT)-guided percutaneous ethanol injection (PEI) using a disposable curved needle for treatment of malignant liver neoplasms and their metastases in retroperitoneal lymph nodes. METHODS: CT-guided PEI was conducted using a disposable curved needle in 26 malignant liver tumors smaller than 5 cm in diameter and 5 lymph node metastases of liver cancer in the retroperitoneal space. The disposable curved needle was composed of a straight trocar (21G) and stylet, a disposable curved tip (25 G) and a fine stylet. For the tumors found in deep sites and difficult to reach, or for hepatic masses inaccessible to the injection using a straight needle because of portal vein and bile ducts, the straight trocar was used at first to reach the side of the tumor. Then, the disposable curved needle was used via the trocar. When the needle reached the tumor center, appropriate amount of ethanol was injected. For relatively large malignant liver tumors, multi-point injection was carried out for a better distribution of the ethanol injected throughout the masses. The curved needle was also used for treatment of the metastasis in retroperitoneal lymph nodes blocked by blood vessels and inaccessible by the straight needle. RESULTS: All of the 26 liver tumors received 2 or more times of successful PEI, through which ethanol was distributed throughout the whole tumor mass. Effect of the treatment was monitored by contrast-enhanced multi-phase CT and magnetic resonance imaging (MRI) examinations three months later. Of the 18 lesions whose diameters were smaller than 3 cm, the necrotic change across the whole mass and that in most areas were observed in 15 and 3 tumors, respectively. Among the 8 tumors sizing up to 5 cm, 5 were completely necrotic and 3 largely necrotic. Levels of tumor seromarkers were significantly reduced in some of the cases. In 5 patients with metastases of liver cancer in retroperitoneal lymph nodes who received 1 to 3 times of PEI, all the foci treated were completely necrotic and smaller demonstrated by dynamic contrast-enhanced CT or MRI 3 months later. CONCLUSION: CT-guided PEI using a disposable curved needle is effective, time-saving and convenient, providing an alternative therapy for the treatment of malignant liver tumors and their retroperitoneal lymph node metastases.

[Pilot study on clinical application of hepatic perfusion with multi-slice spiral CT].

OBJECTIVE: To research the value of hepatic perfusion with multi-slice spiral CT in the diagnosis of liver diseases. METHODS: Among the 48 patients undergone dynamic CT of the liver, 20 were volunteers without hepatic disorder, 17 with cirrhosis, 11 suffered from hepatic cancer. The perfusion indexes were calculated and compared. RESULTS: (1) Compared with the control group, HPP (ml/min/ml), PPI and HPP/HAP of patients with cirrhosis were significant lower (HPP: 0.49+/-0.19 vs 0.60+/-0.16, P=0.038; PPI: 0.58+/-0.14 vs 0.67+/-0.06, P=0.015; HPP/HAP: 1.63+/-0.87 vs 2.12+/-0.65, P=0.04), whereas HPI was higher (0.42+/-0.14 vs 0.33+/-0.06, P= 0.015), which indicated the decrease of portal inflow and the increase of arterial inflow in cirrhosis patients. (2) Patients with hepatic cancer got a significant higher average HAP than that in volunteers and cirrhosis patients (F=11.71, P<0.001), while their HPP and HPP/HAP showed significant declining (F=22.84, P=0.0001; F=20.67, P<0.0001, respectively), which implied that hepatic cancer was mainly supplied by artery. CONCLUSIONS: Hepatic perfusion with multi-slice spiral CT is an non-invasive technique to evaluate the arterial and portal inflow separately, which can inflect the hemodynamic change of the lesion by the perfusion indexes, and identify the condition of the tissue round the lesion prior to morphologic change. This method shows important value of diagnosis and differential diagnosis in hepatic diseases.

[Effect of ginsenoside Rg2 on chemical myocardial ischemia in rats].

OBJECTIVE: To investigate the protective effect of Ginsenoside Rg2 on Chemical myocardial ischemia. METHOD: The models of myocardial ischemia were built in rats with isoproterenol, sodium nitrite,pituitrin. Ginsenoside Rg2 (iv 2.5, 5.0, 10.0 mg x kg(-1)) were intravenously administered. RESULT: Ginsenoside Rg2 could improve the abnormal electrocardiogram (ECG), reduce the arca of myocardial ischemia and improve the abnormal zymologic value of myocardial. CONCLUSION: Ginsenoside Rg2 has inhibitory function on myocardialischemia.

Effect of oviductus ranae and oviductus ranae eggs on bone metabolism and osteoporosis.

OBJECTIVE: To evaluate the roles or effects of oviductus ranae (OR) or oviductus ranae eggs (ORE) in preventing and treating postmenopausal osteoporosis. METHODS: In vivo experiment: Sixty female adult Wistar rats were randomly divided into 5 groups of 12. To provide an osteoporosis model 4 groups of rats were ovariectomized (OVX), with the 5th being sham operated. Medication commenced 7 days after the operation and lasted continuously for 12 weeks. Sham operated and OVX groups were given equivalent volumes of 5% Tween-80. The other three groups intragastrically received conjugated estrogens (CE), OR or ORE of the corresponding doses. At the 12th week, serum estrogen, bone gla protein (BGP), serum calcium, phosphorus, and alkaline phosphatase (ALP) were assayed; bone mineral densities (BMD) were measured and bone scanning was conducted; uteri were weighed, and weight, volume and length of the femoral bones were determined; and cortical thickness of femoral heads and area of bone trabecula were measured by image analyzer. In vitro experiment: Eighty 10-month old SD rats, with equal numbers of males and females, were randomly divided into 8 groups. Osteoblasts were isolated from neonatal rat calvariae, and the cells were exposed to various concentrations of serum from OR and ORE groups to study the impact of these sera on osteoblastic proliferation, ALP activity and mineralization. Osteoclastic numbers were determined using tartrate resistant acid phosphatase (TRAP). RESULTS: In vivo experiment: The body weight of the four OVX groups increased significantly (P<0.01). Uterine weight of the CE group was the highest (P<0.01); Compared with the model group, estrogen level, BMD, bone scanning/bone imaging index weight of the femoral bones, cortical thickness of femoral heads in the OR and ORE groups increased significantly (P<0.05, P<0.01); femoral volume in the ORE group increased significantly (P<0.05); and the content of osteocalcin, phosphorus, and ALP in serum decreased significantly (P<0.05, P<0.01). In vitro experiment: Sera from OR and ORE groups had notable effects on the proliferation of osteoblasts (P<0.05 and P<0.01, repsectively) and stimulated the formation of calcium nodes (P<0.05, P<0.01), while the enhancement of ALP activity in osteoblasts was significant (P<0.05, P<0.01). The number of TRAP-positive cells was significantly reduced as well (P<0.01). CONCLUSIONS: OR and its eggs could effectively suppress OVX-induced osteoporosis in rats, and increase bone turnover possibly by both an increase in osteoblastic activity and a decrease in osteoclastic activity. The present study provides evidence that OR and its eggs could be considered a complementary and alternative medicine for the treatment of postmenopausal osteoporosis.

Quantitative perfusion computed tomography measurements of cerebral hemodynamics: correlation with digital subtraction angiography identified primary and secondary cerebral collaterals in internal carotid artery occlusive disease.

BACKGROUND: The aim of the present study was to assess hemodynamic variations in symptomatic unilateral internal carotid artery occlusion (ICAO) patients with primary collateral flow via circle of Willis or secondary collateral flow via ophthalmic artery and/or leptomeningeal collaterals. METHODS: Thirty-eight patients with a symptomatic unilateral ICAO were enrolled in the study. Based on digital subtraction angiography (DSA) findings, patients were classified into 2 groups: primary collateral (n = 14) and secondary collateral (n = 24) groups. Collateral flow hemodynamics were investigated with perfusion computed tomography (PCT) by measuring the cerebral blood flow (CBF), cerebral blood volume (CBV) and time to peak (TTP) in the hemispheres ipsilateral and contralateral to ICAO. Based on the measurements, the ipsilateral to contralateral ratio for each parameter was calculated and compared. RESULTS: Irrespective of the collateral patterns, ipsilateral CBF was not significantly different from that of the contralateral hemisphere (P = 0.285); ipsilateral CBV and TTP was significantly increased compared with those of the contralateral hemisphere (P=0.000 and P = 0.000 for CBV and TTP, respectively). Furthermore, patients with secondary collaterals had significantly larger ipsilateral-to-contralateral ratios for both CBV (rCBV, P = 0.0197) and TTP (rTTP, P = 0.000) than those of patients with only primary collaterals. These two groups showed no difference in ipsilateral-to-contralateral ratio for CBF (rCBF, P = 0.312). CONCLUSION: Patients with symptomatic unilateral ICAO in our study were in an autoregulatory vasodilatation status. Moreover, secondary collaterals in ICAO patients were correlated with ipsilateral CBV and delayed TTP that suggested severe hemodynamic impairment, presumably increasing the risk of ischemic events.

Relative apparent diffusion coefficient: a promising tool to differentiate metastatic from benign lymph nodes in animal models.

BACKGROUND: Diffusion-weighted imaging has been widely used to differentiate the character of lymphadenopathy. But there are significant differences between prior studies. The aim of the study was to compare the benefit of apparent diffusion coefficient (ADC) and rADC in the differentiation of metastatic and benign lymph nodes in a rabbit model. METHODS: Two observers independently measured ADCs in quadriceps of every rabbit on diffusion-weighted images with different sizes of regions of interest (ROI). The appropriate ROI for rADC was determined using the interobserver coefficient. rADC was calculated by ADC(lesion)/ADC(reference site). Receiver operating characteristics (ROC) analysis was performed to compare the diagnostic value of the ADC values and rADC values in differentiating metastatic from benign lymph nodes. RESULTS: When the ROIs included five pixels, the ICC was 0.816, indicating a good interobserver agreement. The differences of ADC and rADC values between metastatic and benign lymph nodes were both statistically significant. The area under the ROC curve was greater for the rADC than for the ADC. With the rADC criteria of 0.640, the sensitivity and specificity for differentiating metastatic from benign lymph nodes were 93% and 90%, respectively. CONCLUSION: As a reference site, muscles reveal a good repeatability using a small ROI and the rADC may improve diagnostic accuracy for detecting metastatic nodes in animal models.

Reproducibility and accuracy of quantitative assessment of articular cartilage volume measurements with 3.0 Tesla magnetic resonance imaging.

BACKGROUND: Quantitative magnetic resonance imaging (qMRI) of articular cartilage represents a powerful tool in osteoarthritis research, but has so far been confined to a field strength of 1.5 T. The aim of the study was to determine the reproducibility and accuracy of qMRI assessments of the knee cartilage volume by comparing quantitative swine cartilage volumes of the sagittal (sag) multi echo data imagine combination water-excitation (MEDICwe) sequence and the fast low-angle shoot water-excitation (FLASHwe) sequence at 3.0-T MRI to directly measured volumes (DMV) of the surgically removed articular cartilage. METHODS: Test-retest MRI was acquired in 20 swine knees. Two sag FLASHwe sequences and two sag MEDICwe sequences (spatial resolution 0.4 mm × 0.4 mm × 1.0 mm of 3-dimension (3D) were acquired at 3-T MRI in a knee. Articular cartilage volume was calculated from 3D reformations of the MRI by using a manual program. Calculated volumes were compared with DMV of the surgically removed articular cartilage. Knee joint cartilage plates were quantified paired in order. RESULTS: In the knee joint of swine, reproducibility errors (paired analysis) for cartilage volume were 2.5% to 3.2% with sag FLASHwe, and 1.6% to 3.0% with sag MEDICwe. Correlation coefficients between results obtained with qMRI and DMV ranged from 0.90 to 0.98 for cartilage volume. Systematic pairwise difference between results obtained with qMRI and DMV ranged from -1.1% to 2.8%. Random pairwise differences between results obtained with qMRI and DMV ranged from (2.9 ± 2.4)% to (6.8 ± 4.5)%. CONCLUSIONS: FLASHwe and MEDICwe sequences permit highly accurate and reproducible analysis of cartilage volume in the knee joints of swine at 3-T MRI. Cartilage volume reproducibility for the MEDICwe data is slightly higher than the FLASHwe data.

Evaluation of peripheral artery stent with 64-slice multi-detector row CT angiography: prospective comparison with digital subtraction angiography.

PURPOSE: To assess the accuracy of 64-slice multi-detector row computed tomography (MDCT) angiography in the evaluation of peripheral artery in-stent or peristent restenosis, with conventional digital subtraction angiography (DSA) as the reference standard. MATERIALS AND METHODS: Forty-one patients (30 men, 11 women; mean age, 69.8+/-9.2 years) with symptomatic peripheral arterial occlusive disease after peripheral artery stenting (81 stented lesions) underwent both conventional DSA and 64-slice MDCT angiography. Each stent was classified as evaluable or unevaluable, and every stent was divided into three segments (proximal stent, stent body, and distal stent), resulting in 243 segments. For evaluation, stenosis was graded as follows: 1, none or slight stenosis (<25%); 2, mild stenosis (25-49%); 3, moderate stenosis (50-74%); 4, severe stenosis or total occlusion (> or =75%). Two readers evaluated all CT angiograms with regard to narrowing of in-stent or peristent restenosis by consensus. Results were compared with findings of the DSA. RESULTS: Of 81 stents, 62 (76.5%) were determined to be assessable. The metal artifact of the gold marker and motion artifact increased uninterpretability of the images of stents. Overall, 24 of 28 in-stent restenosis and 38 of 53 persistent restenosis were correctly detected by MDCT (85.7% and 71.7% sensitivity). In evaluable stents, 21 of 22 in-stent restenoses and 27 of 28 persistent restenosis were correctly detected (95.4% and 96.4% sensitivity). Additionally, as the grade of stenosis increases, the mean level of CT values in the stent lumina decreases linearly accordingly. CONCLUSION: 64-Slice MDCT has a high accuracy for the detection of significant in-stent or peristent restenosis of assessable stents in patients with peripheral artery stent implantation and therefore can be considered as a valuable noninvasive technique for stent surveillance.