Normal and stenotic renal arteries: experimental balloon-expandable intraluminal stenting

Elastic recoil of the vessel wall is a common cause of failure of percutaneous transluminal angioplasty in renal arteries. To oppose such recoil, balloon-expandable metal stents were implanted in artificially stenotic renal arteries in pigs and normal renal arteries in dogs and pigs. The stents were then examined angiographically and histologically at regular intervals. All stents were completely covered with endothelialized neointima in 3 weeks. There was no difference in intimal thickness between the stenotic and nonstenotic renal arteries. A large stent diameter and a large open or nonmetal surface may cause less intimal hyperplasia, but nonturbulent, fast arterial flow is probably the most important factor in ensuring long-term patency of the vessel.     

Computer-aided detection (CAD) of lung nodules in CT scans: radiologist performance and reading time with incremental CAD assistance

Objective

The diagnostic performance of radiologists using incremental CAD assistance for lung nodule detection on CT and their temporal variation in performance during CAD evaluation was assessed.

Methods

CAD was applied to 20 chest multidetector-row computed tomography (MDCT) scans containing 190 non-calcified ≥3-mm nodules. After free search, three radiologists independently evaluated a maximum of up to 50 CAD detections/patient. Multiple free-response ROC curves were generated for free search and successive CAD evaluation, by incrementally adding CAD detections one at a time to the radiologists’ performance.

Results

The sensitivity for free search was 53% (range, 44%–59%) at 1.15 false positives (FP)/patient and increased with CAD to 69% (range, 59–82%) at 1.45 FP/patient. CAD evaluation initially resulted in a sharp rise in sensitivity of 14% with a minimal increase in FP over a time period of 100 s, followed by flattening of the sensitivity increase to only 2%. This transition resulted from a greater prevalence of true positive (TP) versus FP detections at early CAD evaluation and not by a temporal change in readers’ performance. The time spent for TP (9.5 s?±?4.5 s) and false negative (FN) (8.4 s?±?6.7 s) detections was similar; FP decisions took two- to three-times longer (14.4 s?±?8.7 s) than true negative (TN) decisions (4.7 s?±?1.3 s).

Conclusions

When CAD output is ordered by CAD score, an initial period of rapid performance improvement slows significantly over time because of non-uniformity in the distribution of TP CAD output and not to a changing reader performance over time.     

Paramagnetic macrocyclic complexes as contrast agents for MR imaging: proton nuclear relaxation rate enhancement in aqueous solution and in rat tissues

Paramagnetic macrocyclic chelates show promise as magnetic resonance (MR) imaging contrast agents due to stability and relaxivity comparable to those of DTPA-type chelates. For the three copper and manganese macrocyclic complexes studied in aqueous solution, T1 and T2 relaxivities ranged from 0.14 to 5.88 mM-1sec-1 at 6.25 MHz. In rats, the intravenous administration of 16 mumol/kg of Mn(cyclam) caused the liver T1 relaxation rate to double at 15 minutes after injection. T1 measurements by pulsed MR imaging and manganese analyses on excised tissue showed that both relaxation rate (1/T1) and manganese content of liver and kidney increase linearly with the dosage of Mn(cyclam). The linear relationship between 1/T1 and manganese content can be considered an "in tissue" relaxivity plot for the agent. The resulting relaxivity is 54 mM-1sec-1 in liver, compared with 3.1 mM-1sec-1 in aqueous solution. Although this work is preliminary, the implication for medical MR imaging applications is that macrocyclic contrast agents can be effective at approximately one-tenth the current typical dose used for gadolinium DTPA.     

Perioperative outcomes and costs of laparoscopic versus open inguinal hernia repair

Purpose

Studies comparing laparoscopic (LIHR) vs. open inguinal hernia repair (OIHR) have shown similar recurrence rates but have disagreed on perioperative outcomes and costs. The aim of this study is to compare laparoscopic vs. open outcomes and costs.

Methods

The National Surgical Quality Improvement Program (NSQIP) was used to compare durations of surgery, anesthesia time, and length of stay (LOS). The University HealthSystem Consortium (UHC) was used to review the cost and complications between approaches. Patients were matched on demographics, year of procedure and surgical approach between datasets for statistical analysis.

Results

A sample of 5468 patients undergoing OIHR (N = 4,693) or LIHR (N = 775) was selected from UHC from 2008–2011. An identical number of patients from NSQIP were matched to those from UHC resulting in a total of 10,936 records. LIHR patients had shorter duration of wait from admission to operation (p < 0.05). Conversely, LIHR patients had longer operating time (p < 0.05), duration of anesthesia (p < 0.05), and time in the operating room (p < 0.05).Overall complication rate was higher in open (3.1 vs. 1.8 %, p < 0.05). Cost favored open over LIHR ($4360 vs $5105). The cost discrepancy mainly stemmed from LIHR supplies ($1448 vs. $340; p < 0.05) and OR services ($1380 vs. $1080; p < 0.05).

Conclusion

This study demonstrates the LOS and perioperative outcomes were superior in the LIHR group; however, the overall cost was higher due to the supplies. Advancement in technology, surgeons’ skill level and preference of supplies are all factors in decreasing the overall cost of LIHR.

     

The position of the anal dimple in newborns and infants with anorectal malformations and its correlation with the normal anal position

Background/purpose

The anal position index (API) defines the normal anal position as the ratio of fourchette–anal distance to fourchette–coccyx distance for females and the scrotum–anal distance to scrotum‐coccyx distance for males. In this study, measurement of the API in newborns and infants with anorectal malformations (ARM), using the center of the midline anal dimple (AD) to represent the center of the proposed neoanus, was performed to assess whether or not the AD was located in a significantly abnormal position as correlated with the normal anal position.

Comparison of Functional Outcomes,Femoral Rollback and Sagittal Stability of Anterior-Stabilized Versus Posterior-Stabilized Total Knee Arthroplasty: A Systematic Review and Meta-analysis of Randomized Controlled Trials

PurposeTotal knee arthroplasty (TKA) has improved leaps and bounds in terms of design to improve clinical outcomes and achieve better rehabilitation of the patients. Ultra-congruent inserts (UC) were designed to replace the need for posterior stabilized (PS) implants. The purpose of this review was to evaluate clinical outcomes, femoral rollback, functional scores, range of motion, sagittal laxity, complication rates, and isokinetic performance between UC and PS TKA among RCTsMethodsElectronic databases such as PubMed, Scopus, opengrey, and Cochrane were searched from date of inception up to mid-April 2021, and meta-analysis was performed following PRISMA guidelines. This study analyzed outcomes, femoral rollback, tibial sagittal laxity and isokinetic performance.ResultsTen RCTs identified 852 knees, of which 420 underwent UC TKAs and 432 underwent PS TKA. Compared to UC TKA, a significantly better sagittal stability (p = 0.17) and femoral rollback (p < 0.00001) in PS TKAs was noted, although no statistically significant difference was found in the assessment of the range of motion (p = 0.19) and functional scores. Both the groups had similar isokinetic performance with extensor torque (p = 0.97) and flexor torque (p = 0.37).ConclusionsWe conclude with the current meta-analysis that there are no added benefits for UC over PS inserts and these inserts have a higher sagittal laxity and less femoral roll back in cruciate sacrificing UC knee. But since there are no long-term wear data, UC inserts with CS technique should be used cautiously and may be used only when the PCL cannot be balanced adequately. There is no evidence or only a few to support the superiority of the AS TKA in terms of clinical outcomes or isokinetic performance or femoral external rotation over PS TKA.Level of EvidenceLevel I, Systematic review and meta-analysis of RCTs.     

CT结肠成像对有临床症状的结直肠癌病人的排除诊断

目的 CT结肠成像技术已经越来越多地用于有结直肠症状病人的影像学评价。本研究的目的是评价CT结肠成像技术对有临床症状的老年病人在排除结直肠癌的诊断中的作用。方法对2002年3月—2007年12月间进行CT结肠成像的1359例病人进行回顾性分析。金标准是一年内的内镜检查结果和(或)至数据分析时临床、内镜及影像学检     

A Geospatial Analysis of Factors Affecting Access to CT Facilities: Implications for Lung Cancer Screening

ObjectiveThe association between access to CT facilities for lung cancer screening and population characteristics is understudied. We aimed to determine the relationship between census tract–level socioeconomic characteristics (SEC) and driving distance to an ACR-accredited CT facility.MethodsCensus tract–level SEC were determined from the US Census Bureau. Distance to nearest ACR-accredited CT facility was derived at the census tract level. Census tract–level multivariable regression modeling was used to determine the relationship between driving distance to a CT facility and census tract SEC, including population density (a marker of rural versus urban), gender, race, insurance status or type, and education level.ResultsIn an adjusted multivariable model, census tract–level population density was the greatest relative determinant of distance to a CT facility. Namely, rural census tracts had relatively longer distances to CT facilities than urban census tracts (P < .001). Census tracts with higher uninsured, Medicaid, undereducated (less <high school degree) populations had relatively greater distances to CT facilities (p<0.001), whereas those with higher non-White, female, and Medicare populations had shorter distances (p<0.001).DiscussionRural populations have relatively less geographic access to CT facilities. Furthermore, other vulnerable populations, such as the uninsured, those on Medicaid, and the undereducated, may also have relatively less access to CT imaging facilities. These variations in access to CT may affect the uptake and utilization of lung cancer screening.