Second Percutaneous Transluminal Angioplasty Versus Surgical Reconstruction for Hemodialysis Access Failure Within a Short Time Period.

BACKGROUND: The purpose of this study was to compare patency and nonabandonment rates for second percutaneous transluminal angioplasty (PTA) and surgical reconstruction for the treatment of failing vascular access due to restenosis or reocclusion in a short time after initial PTA. METHODS: Seventy two consecutive patients who underwent second treatment within 90 days after the initial PTA were evaluated retrospectively. The patency (time to corrective procedure) and access abandonment were compared among patients who underwent a second PTA (n = 35) and those who underwent surgical reconstruction (n = 37). Univariate and multivariate analyses were performed to determine independent predictors of patency and access abandonment at 1 year after the treatment. RESULTS: At 1 year after the treatment, the patency rates were 35.1% and 11.4% (P = 0.02) and nonabandonment rates were 64.9% and 77.1% (P = 0.25) for surgical reconstruction and second PTA, respectively. The Kaplan-Meier survival analysis showed that the surgical reconstruction group had better patency probability (P = 0.02), but there was no difference in the nonabandonment probability between the groups (P = 0.29). Shorter time to retreatment was associated with good patency. The female gender was likely to be associated with access abandonment. CONCLUSIONS: The access abandonment between the 2 procedures had no difference, although surgical reconstruction provided better patency than second PTA.

Additive value of 320-section low-dose dynamic volume CT in relation to 3-T MRI for the preoperative evaluation of brain tumors.

PURPOSE: To assess whether 320-section low-dose dynamic volume computed tomography (320-LDVCT) with adaptive iterative dose reduction (AIDR) adds value to 3-T MRI for the preoperative evaluation of brain tumors. METHODS: The study population was comprised of 16 consecutive patients with brain tumors who, in addition to preoperative 3-T MRI, underwent 320-LDVCT with AIDR. Two radiologists independently evaluated the CT and MRI studies; one measured the relative cerebral blood volume (rCBV) in the tumor and contralateral brain on CT and MR perfusion maps. Interobserver agreement was assessed by κ statistics. RESULTS: In 3 of 16 patients (19 %), 320-LDVCT added diagnostic value to 3-T MRI studies with respect to the visualization of feeders (κ = 0.77), and in 12 (75 %) it helped the delineation of venous structures (κ = 0.71) and the relationship between the tumor and adjacent vessels (κ = 0.85). The average standardized rCBV value was 12.2 ± 2.40 (range 0.7-36.6) on MR and 8.80 ± 2.77 (range 0.8-38.0) on CT perfusion studies; the correlation between these values was very strong (r = 0.92, p < 0.0001). According to the neurosurgeons, 320-LDVCT added helpful information for surgery in 4 patients (25 %). CONCLUSION: The 320-LDVCT can add value to 3-T MRI for the tumor feeders and relationship between the tumor and adjacent vessels.

Evaluation of Intracranial Vasculatures in Healthy Subjects with Arterial-Spin-Labeling-Based 4D-MR Angiography at 3T.

Contrast inherent inflow-enhanced multi-phase angiography combining multiple-phase flow-alternating inversion-recovery (CINEMA-FAIR) is an arterial-spin-labeling-based four-dimensional magnetic resonance angiography (4D-MRA) technique. Two neuroradiologists independently evaluated the depiction of the intracranial vasculatures in healthy subjects with 3T 4D-MRA using CINEMA-FAIR. Our results indicated that this technique can provide good visualization of the cerebral arteries with a high spatial and temporal resolution. It appears to have sufficient resolution for identifying flow difference in the anterior and posterior circulation in healthy subjects.

Can CT angiography reconstructed from CT perfusion source data on a 320-section volume CT scanner replace conventional CT angiography for the evaluation of intracranial arteries?

PURPOSE: To compare conventional CT angiography (CTA) and CTA reconstructed from CT perfusion source data (perfusion CTA) acquired on a 320-section CT scanner for the evaluation of intracranial arteries. MATERIALS AND METHODS: Our study included 7 patients who had undergone trapping of an intracranial aneurysm and placement of a bypass. All underwent conventional and perfusion CTA and digital subtraction angiography (DSA). Using DSA as the gold standard, 2 radiologists evaluated 10 arterial segments on conventional and perfusion CTA images. On a 4-point scale they independently scored the image quality and vascular visualization of the intracranial arteries on the conventional and perfusion CTA images. The effective radiation dose to each patient was also recorded. RESULTS: A total of 65 arterial segments without apparent abnormalities were assessed. While the mean image quality score tended to be slightly higher for conventional than perfusion CTA, there was no significant difference. The effective dose for perfusion and conventional CTA with unenhanced CT was 4.2 mSv and 3.1 mSv, respectively, for all patients. CONCLUSION: For the evaluation of intracranial arteries using DSA as the gold standard, perfusion CTA yields image quality and vascular visualization similar to conventional CTA at an acceptable radiation dose.

Incidence and severity of acute adverse reactions to four different gadolinium-based MR contrast agents.

PURPOSE: Differences in acute adverse reactions to different gadolinium (Gd)-based contrast agents have not been thoroughly evaluated. We investigated the relationships among the incidence and severity of acute adverse reactions, backgrounds of patients, and 4 types of different Gd-based contrast agents (gadopentetate dimeglumine, gadoteridol, gadoterate meglumine, and gadoxetate disodium). MATERIALS AND METHODS: We retrospectively reviewed the radiological records of 10,595 consecutive patients (4,343 female; 6,252 male; mean age, 63.8 ± 14.0 years) who underwent contrast-enhanced magnetic resonance imaging between August 2006 and March 2011. Adverse reactions were classified as mild, moderate, and severe according to the definition of the American College of Radiology. The incidence of adverse reactions were compared on the basis of clinical characteristics and type, dose, and delivery methods of contrast agents by univariate and multivariate logistic regression analyses. RESULTS: The incidence of overall reactions was 0.45% (48/10,595); 45 reactions were mild and three were moderate. No severe reactions were observed. Although the incidence of adverse reactions did not differ significantly between male and female patients, younger individuals were at higher risk for acute adverse reactions. The contrast injection rate and contrast dose were not significantly related to the incidence of adverse reactions. The incidence of adverse reactions was significantly higher for gadoxetate disodium (0.82%) than gadopentetate dimeglumine (0.43%). CONCLUSION: The incidence of acute adverse reactions elicited by Gd-based contrast agents injection was only 0.45%. Younger age was a risk factor for acute reactions. All 4 agents were found to be safe, although gadoxetate disodium showed a relatively higher incidence of adverse reactions.

Spinal imaging features in Japanese patients with Marfan syndrome: a case-control study.

PURPOSE: The purpose of our study was to evaluate the morphology of the lumbosacral spine, i.e. the dura and vertebral body shape, of Japanese patients with Marfan syndrome (MFS) by comparing it with sex- and age-matched controls. MATERIALS AND METHODS: Spinal MR or CT images of 32 MFS patients and 32 controls were retrospectively reviewed. The anteroposterior dural sac diameter (DSD), anteroposterior vertebral body diameter (VBD), and vertebral body height (VBH) were measured from L1 to S1 levels and the dural sac ratio [DSR = (DSD/VBD)] and vertebral body aspect ratio [VAR = (VBH/VBD)] were calculated. RESULTS: At each level, mean DSD and DSR were significantly higher in MFS patients; VBD was not. The cutoff values for DSR to differentiate between MFS patients and the controls were 0.59, 0.46, 0.42, 0.45, 0.47, and 0.47 from the level of L1 to S1. At a sensitivity of 93.8 % and a specificity of 84.4 % the cutoff value at S1 was most diagnostic. In MFS patients VAR was significantly higher at L3 and L4. CONCLUSION: Our cutoff value for DSR >0.47 at S1 may help to identify MFS in the Japanese population. A square-like appearance of the L3 and L4 vertebral bodies is a supplementary finding in MFS patients.

Can sufficient preoperative information of intracranial aneurysms be obtained by using 320-row detector CT angiography alone?

PURPOSE: To determine whether sufficient pre-surgical treatment information of unruptured intracranial aneurysms can be obtained by using 320-row detector CT angiography (CTA) alone. MATERIALS AND METHODS: We enrolled 40 consecutive patients with unruptured intracranial aneurysms. All patients were prospectively conducted to perform 320-detector CTA as the only preoperative modality. Two blinded readers independently assessed CTA images. Interobserver agreement and the agreement between CTA and surgical findings were determined by calculating the κ coefficient. The referring neurosurgeons judged the usefulness of the information provided by CTA for treatment decisions. RESULTS: All patients had surgery without intraarterial digital subtraction angiography. Agreement between CTA and surgical findings was excellent for the aneurysm location (κ = 1.0) and good for the shape (κ = 0.71), neck (κ = 0.74) and its relationship with adjacent branches (κ = 0.71). Information obtained with 320-detector CTA was highly useful for surgical treatment in 37 of 40 (93 %) patients, although small perforators deriving from the aneurysm in 2 cases were not fully visualized on CTA images. CONCLUSION: In most patients with unruptured intracranial aneurysms, sufficient pre-surgical treatment information can be obtained by using 320-detector CTA alone.

Added value of high-b-value (b = 3000 s/mm2) diffusion-weighted imaging at 3 T in relation to fluid-attenuated inversion recovery images for the evaluation of cortical lesions in inflammatory brain diseases.

OBJECTIVE: The purpose of this study was to determine how the gray-to-white matter contrast in healthy subjects changes on high-b-value diffusion-weighted imaging (DWI) acquired at 3 T and evaluate whether high-b-value DWI at 3 T is useful for the detection of cortical lesions in inflammatory brain diseases. METHODS: Ten healthy volunteers underwent DWI at b = 1000, 2000, 3000, 4000, and 5000 s/mm(2) on a 3-T MRI unit. On DW images, 1 radiologist performed region-of-interest measurements of the signal intensity of 8 gray matter structures. The gray-to-white matter contrast ratio (GWCR) was calculated. Ten patients with inflammatory cortical lesions were also included. All patients underwent conventional MRI and DWI at b = 1000 and 3000 s/mm(2). Using a 4-point grading system, 2 radiologists independently assessed the presence of additional information on DW images compared with fluid-attenuated inversion recovery images. Interobserver agreement was assessed by κ statistics. RESULTS: In the healthy subjects, the b value increased as the GWCR decreased in all evaluated gray matter structures. On DW images acquired at b = 3000 s/mm(2), mean GWCR was less than 1.0 in 7 of 8 structures. For both reviewers, DWI at b = 3000 s/mm(2) yielded significantly more additional information than did DWI at b = 1000 s/mm(2) (P < 0.05). Interobserver agreement for DWI at b = 1000 s/mm(2) and b = 3000 s/mm(2) was fair (κ = 0.35) and excellent (κ = 1.0), respectively. CONCLUSIONS: At 3-T DWI, the gray-to-white matter contrast in most gray matter structures reverses at b = 3000 s/mm. In the evaluation of cortical lesions in patients with inflammatory brain diseases, 3-T DWI at b = 3000 s/mm was more useful than b = 1000 s/mm(2).