Arash Ehteshami Rad

Cerebral venous sinus density on noncontrast CT correlates with hematocrit.

BACKGROUND AND PURPOSE: A positive correlation between HCT and CT attenuation of intravascular blood has long been assumed but has never been established by using substantial patient numbers and modern CT equipment. The purpose of this study was to determine whether apparent increased attenuation on CT in cerebral venous sinuses can be attributed to hemoconcentration alone and to assess whether sinus thrombosis can be differentiated from hemoconcentrated blood based on attenuation values alone. MATERIALS AND METHODS: We measured HUs in a region of interest within the confluence of dural venous sinuses in 166 unenhanced head CTs and correlated these data with HCT and HGB values in male and female patients aged 2 to 100 years. We then compared these data with similar measurements in 8 patients with recent venous sinus thrombosis. Two-tailed t test and linear regression analyses were performed to evaluate HGB and HCT between groups and with measured CT attenuation of intravascular blood, respectively. RESULTS: A statistically significant relationship was noted between both HCT and HGB with CT attenuation. Seven of 8 patients with sinus thrombosis had attenuation values >70, but none of the normal subjects had HUs >70. CONCLUSIONS: Hemoconcentration correlates with CT attenuation in cerebral venous sinuses. Our findings suggest that comparing the ratio of HUs to HCT may be useful in gauging concern for sinus thrombosis.

Impact of Self-citation on the H Index in the Field of Academic Radiology

RATIONALE AND OBJECTIVES The Hirsch Index (H index) is widely applied as a metric of scientific productivity. The purpose of this study was to evaluate the role of self-citation on the H index in academic radiology. MATERIALS AND METHODS Through the National Resident Matching Programs Web site, one third (47/139) of radiology residency programs were selected randomly. All chairpersons and full professors were included. Using the Scopus database, we calculated the H index as well as the number of cumulative citations with and without inclusion of self-citations. We determined the proportion of academic staff in which H index increased by one, two, or greater than two integers. We also correlated the proportional increase in H index before and after inclusion of self citations with the number of publications. RESULTS A total of 487 academic staff (47 chair and 440 professors) was identified. Because of self-citation, mean ± SD of the H index increased from 13.7 ± 9.9 to 14.0 ± 10.2; mean ± SD of cumulative citations increased from 1804 ± 1889 to 1870 ± 1971. H index numbers did not change in 376/487 (77%) authors as a result of self-citation. There was no correlation between number of publications and proportional change of H index. CONCLUSION The effect of self-citation is minimal in academic radiology, as evidenced by the fact that cumulative citations increase by only 2% and the large majority of H index values do not change by even a single integer after inclusion of self-citation.

Asymptomatic and Unrecognized Cement Pulmonary Embolism Commonly Occurs with Vertebroplasty

BACKGROUND AND PURPOSE: Cement PE represents a potentially serious complication following vertebroplasty. To determine the frequency and extent of cement PE during percutaneous vertebroplasty, we performed a retrospective review of chest CT scans obtained in patients who had previously undergone ≥1 vertebroplasty procedure. MATERIALS AND METHODS: After approval by our local institutional review board, we retrospectively evaluated 244 patients who had undergone vertebroplasty at 465 levels and subsequently underwent chest CT. A thoracic radiologist evaluated the presence, number, size, and location of discrete cement PEs. We catalogued the following data: age, sex, number of treated vertebrae, cement volume per vertebra, operator, presence of cement leakage noted by the operator during the procedure, and clinical presentation at postvertebroplasty CT. RESULTS: At least 1 cement PE was detected in 23 (9.4%; 95% CI, 6%–13%) of 244 patients; 1 patient was symptomatic from a cement PE. The mean number of discrete cement PEs was 3.2 ± 3.4 (median, 2; range, 1–12). There was no correlation among the total number of treatment sessions, number of levels treated per session, cement volume per level, operator, or time between vertebroplasty and chest CT in the detection of cement PE. Those with PE were significantly younger (P = .0229) and had significantly more total levels treated (P = .0260). Cement PE was recognized by the operator during the vertebroplasty in 2 (8.7%) of 23 patients found to have it on CT. CONCLUSIONS: Small asymptomatic cement PEs are common during vertebroplasty and usually are not recognized by the operator during the procedure.

Patency of Branches after Coverage with Multiple Telescoping Flow-Diverter Devices: An In Vivo Study in Rabbits

BACKGROUND AND PURPOSE: The safety of placing multiple overlapped endoluminal flow diverters remains unclear because small eloquent branch arteries theoretically could become occluded by these devices. We placed single and multiple flow diverters over small branch arteries in rabbit aortas to determine the incidence of branch artery occlusion. MATERIALS AND METHODS: Flow diverters (PED) were placed into 22 female New Zealand white rabbits abdominal aortas to cover ≥1 lumbar artery. Animals were divided into 3 groups (single PED, n = 9; double PED with 2 telescoped/overlapped devices, n = 7; and triple PED, with 3 telescoped/overlapped devices, n = 6) and were followed for 6 or 12 months. DSA was performed at follow-up. Subsequently, the tissue was processed, sectioned, and stained with H&E for histologic evaluation, histomorphometry, and analysis. RESULTS: All the lumbar arteries covered by devices were clearly patent on angiography. Partial neointima covered the ostia of the branch vessels, but demonstrable patent lumens at the ostia in all cases were present. Neointima hyperplasia was minimal in the single-PED-group animals. The measured neointima was thicker for the double- and triple-PED groups compared with the single-PED group (P < .05). However, in all groups, the mean thickness of the neointima was ≤0.2 mm, and the percentage stenosis of the parent artery was <15% and 18% for 6 and 12 months, respectively. There was no significant inflammatory response in any group. CONCLUSIONS: Small branch arteries remain patent even when covered by multiple overlapped PED flow-diverter devices.

Prevalence of extravertebral cement leakage after vertebroplasty: procedural documentation versus CT detection.

Background Reported incidence of extravertebral cement leakage after vertebroplasty varies widely across studies. Purpose To retrospectively compare the relative detection rates of extravertebral leakage noted under intra-procedural fluoroscopic surveillance, postprocedure plain radiographs, and postprocedure computed tomography (CT) in a cohort of patients undergoing vertebroplasty. Material and Methods With IRB approval, we retrospectively identified 181 patients with 277 levels treated with percutaneous vertebroplasty among a total of 1255 patients undergoing vertebroplasty between 1999 and 2010 who had subsequently undergone a CT examination that included the treated level(s). Categories of leakage were paravertebral, end plate, epidural, and prevertebral venous leakage. CT-detected leak rates were then compared to those noted on the vertebroplasty procedure reports and the archived fluoroscopic images for this same cohort using Pearsons χ2 test. Results One hundred and forty-nine (82%, 95% CI 76–87%) of 181 patients demonstrated evidence of some type of leakage on CT at one or more treated levels. Sixty-two (34%, 95% CI 28–42%) and seventy-seven (50%, 95% CI 43–57%) of 149 CT-detected leaks were reported in the procedural dictation or detected on plain radiography (P = 0.01 and 0.006, respectively). The most common type of leakage noted on CT was end plate (n = 81, 45%, 95% CI 38–52%), followed by paravertebral (n = 64, 35%, 95% CI 29–43%), epidural (n = 36, 20%, 95% CI 15–26%), and prevertebral venous (n = 32, 18%, 95% CI 13–24%). Conclusion Cement leakage after vertebroplasty is common and is often not reported by operators in procedural dictations. CT detects substantially more leaks than plain radiography.

Correlation between preoperative pain duration and percutaneous vertebroplasty outcome.

BACKGROUND AND PURPOSE: The duration of the fracture is considered by many practitioners to be an important predictor of outcome following vertebroplasty. We sought to define the impact of preprocedural pain duration on outcomes, including pain relief, improvement in function, and medication usage among patients treated with single-level vertebroplasty. MATERIALS AND METHODS: Institutional review board approval was obtained before conducting this retrospective analysis of 321 patients undergoing single-level vertebroplasty at our institution. Fractures were categorized as acute (≤6 weeks, n = 153), subacute (6–24 weeks, n = 124), and chronic (>24 weeks, n = 44). Pain NRS (0–10) scores at rest and with activity and RDS were compared among 3 groups at baseline and post procedure. Also absolute and proportional improvement of pain NRS and RDS were compared among 3 groups by using ANOVA. Linear regression was performed between preoperative pain duration and symptom improvement for each group. RESULTS: Baseline RDS and pain NRS with activity and at rest were not significantly different among groups (P = .09, .30, and .91, respectively). Mean improvement in pain NRS with activity at 1 month postvertebroplasty in acute (improvement = 4.9 ± 3.5), subacute (improvement = 4.2 ± 3.2), and chronic fractures (improvement = 4.5 ± 3.2) was similar among groups (P = .28). Mean improvement in RDS at 1 month postprocedure was 9.6, 8.3, and 9.9, for acute, subacute, and chronic fractures, respectively (P = .56). There was no strong correlation between length of pain and symptom improvement. CONCLUSIONS: The age of fracture has minimal impact on outcome following single-level vertebroplasty, with good outcomes noted among patients with acute, subacute, and chronic fractures.

Correlating first- and second-rib fractures noted on spine computed tomography with major vessel injury

First- and second-rib fractures diagnosed on plain radiographs have been associated with traumatic aortic injury. We examined whether such fractures diagnosed on computed tomography (CT), which is of greater sensitivity than plain radiograms for rib fractures, are associated with traumatic vascular injury. We identified 1,894 patients who had undergone a chest CT angiogram with indication of trauma between 2005 and 2008. Among these, 185 patients were selected at random. The main mechanism of injury was motor vehicle accident or a fall. The patients were divided into two groups: patients with first- and/or second-rib fractures and those without. Proportions of patients with major vessel injury noted on CT angiography were compared between groups. Information regarding displacement of the fracture, location of the fracture, detection upon plain film, and gender of the patients was also evaluated and correlated with incidence of major vessel injury. Fisher’s test and χ2 analysis were used to determine significance of the data. Incidence of major vessel injury was similar between patients with and without first- and/or second-rib fractures (7% vs. 9%, respectively; p = 0.59). No subset of type of rib fracture was associated with greater incidence of aortic injury. First- and second-fractures are not associated with greater incidence of aortic injury. Thus, the previous axiom that first- and second-rib fractures should result in increased examination for aortic injury may not hold true.

Neither Subendplate Cement Deposition nor Cement Leakage into the Disk Space during Vertebroplasty Significantly Affects Patient Outcomes

PURPOSE To determine the impact of cement placement immediately adjacent to and through the endplate during percutaneous vertebroplasty on postprocedural pain and subsequent fracture rate. MATERIALS AND METHODS Institutional review board approval with waived consent was obtained. Medical records of 424 patients undergoing first-time, single-level vertebroplasty for osteoporotic or traumatic compression fractures were examined. Data regarding pain at rest and with activity before the procedure, along with timing and level of subsequent fractures over a 24-month period, were collected. Group 1 (n=64) included patients with no cement extension to the endplate(s), group 2 (n=216) included those with cement extension to the endplate(s) but no leakage into the disk space(s), and group 3 (n=144) included those with cement extension to the endplate(s) and cement leakage into the disk space(s). Analysis of variance and Fisher test were used to analyze the data, with significance set at P<.05. RESULTS Baseline characteristics and demographics were similar among the groups. At 1 month, for groups 1, 2, and 3, the respective mean postprocedural pain numeric scores at rest were 1.4±2.7, 1.4±2.4, and 1.6±2.5 (P=.51), while the respective pain scores with activity were 4.3±2.9, 3.8±3.1, and 3.9±3.3 (P=.50). Total subsequent fractures were noted in five (8%), 26 (12%), and 15 (10%) patients in group 1, 2, and 3, respectively (P=.77). CONCLUSION Neither extension of cement to the endplate nor cement leakage into the disk space has significant impact on postprocedural pain or subsequent fracture rate at 2 years.

Role of physical activity in new onset fractures after percutaneous vertebroplasty

Background Increased mobility and physical activity after successful vertebral augmentation procedure might increase the risk of new-onset fractures. Purpose To determine whether new-onset fracture following vertebroplasty is associated with specific type of physical activity. Material and Methods A total of 107 patients underwent at least two procedures of percutaneous vertebroplasty. Among them, 30 patients who sustained a post-vertebroplasty fracture(s), were stratified by fracture-causing activity and examined the incidence of the initial and post-vertebroplasty fractures, time to post-vertebroplasty fractures, duration of anti-osteoporotic therapy, T-score, and body mass index. Results The following percentages correspond to patients with fractures sustained pre- and post-vertebroplasty, respectively; spontaneous fractures in 17% and 7% (P = 0.20), sitting in 7% and 3% (P = 0.50), walking or standing in 7% and 20% (P = 0.10), housework in 3% and 3% (P > 0.99), coughing or sneezing in 0% and 20% (P = 0.003), exercise in 7% and 17% (P = 0.20), lifting in 10% and 17% (P = 0.40) and falling in 50% and 13% (P = 0.002). Different levels of activity were not significantly associated with time to incidence of post-vertebroplasty fractures. Anti-osteoporotic medications were administered to 33% of patients before vertebroplasty and 37% after the vertebroplasty (P = 0.78); medications were administered to these groups for 16 and 25 months, respectively (P = 0.39). Conclusion A significantly elevated risk of new onset fracture with increased physical activity was not identified. However, patients should be carefully counseled after vertebroplasty to optimize medical therapy for osteoporosis and also to use extreme care when engaging in even moderate physical activity.

Incident Vertebral Fractures in Patients not Undergoing Vertebroplasty

PURPOSE To determine whether vertebroplasty increases the risk of new (ie, incident) vertebral fractures by comparing the rates of incident fractures among a group of patients with painful vertebral fractures who did not undergo vertebroplasty with a group of patients who did. MATERIALS AND METHODS A retrospective chart review was performed to identify new-onset fractures after initial vertebroplasty evaluation in two groups, including patients who underwent vertebroplasty within 1 week of initial evaluation (group 1) and those who did not (group 2). Group 2 was further limited to patients with acute or subacute prevalent fractures (group 2A) after exclusion of those with exclusively chronic prevalent fractures. Survival analyses were performed to compare time to diagnosis and frequency of incident fractures in these three groups of patients. RESULTS Group 1 included 269 patients, group 2 included 107 patients, and group 2A included 82 patients. Compared with group 2, incident fractures in group 1 occurred significantly earlier (log-rank statistic, 0.01) and more frequently (hazard ratio, 2.9; 95% CI, 1.2-8.4). CONCLUSIONS Among patients with acute or subacute vertebral fractures presenting for consideration of vertebroplasty, those who undergo the procedure experience more and earlier incident fractures than those who do not, but the observed differences failed to reach statistical significance. Further work is needed in this area to better define relative risks of incident fracture between treated and nontreated patients.