Nonvascular Interventional Procedures in an Urban General Hospital: Analysis of 2001-2010 with Comparison to the Previous Decade

Iatrogenic vascular complications of non-vascular percutaneous abdominal procedures

PURPOSE

The purpose of this paper is to compile and present all of the reported vascular complications that resulted from common non-vascular abdominal procedures in the literature. Non-vascular procedures include, though are not limited to, percutaneous abscess/fluid collection drainage (PAD), percutaneous nephrostomy (PN), paracentesis, percutaneous transhepatic cholangiography (PTC)/percutaneous biliary drainage (PBD), percutaneous biliary stone removal, and percutaneous radiologic gastrostomy (PG)/percutaneous radiologic gastrojejunostomy (PG-J). By gathering this information, radiologists performing these procedures can be aware of the associated vascular injuries, as well as take steps to minimize risks.

METHODS

A literature review was conducted using the PubMed database to catalog relevant articles, published in the year 2000 onward, in which an iatrogenic vascular complication occurred from the following non-vascular abdominal procedures: PAD, PN, paracentesis, PTC/PBD, percutaneous biliary stone removal, and PG/PG-J. Biopsy and tumor ablation were deferred from this article.

RESULTS

214 studies met criteria for analysis. 28 patients died as a result of vascular complications from the analyzed non-vascular abdominal procedures. Vascular complications from paracentesis were responsible for 19 patient deaths, followed by four deaths from PTC/PBD, three from biliary stone removal, and two from PG.

CONCLUSION

Despite non-vascular percutaneous abdominal procedures being minimally invasive, vascular complications still can arise and be quite serious, even resulting in death. Through the presentation of vascular complications associated with these procedures, interventionalists can improve patient care by understanding the steps that can be taken to minimize these risks and to reduce complication rates.

Guayule Natural Rubber Latex and Bi2O3 Films for X-ray Attenuating Medical Gloves

Existing natural latex radiation-attenuating gloves (RAGs) contain a high loading of radiation attenuation filler that reduces their mechanical properties to below Food and Drug Administration (FDA) medical glove requirements. RAGs are commonly formulated using Hevea natural rubber latex and lead-based fillers. The former can cause life-threatening allergic responses and the latter are known for their toxicity. In this work, a new lead-free RAG formulation based on circumallergenic guayule natural rubber latex (GNRL) and non-toxic radiation attenuation filler bismuth trioxide (Bi₂O₃) was developed. GNRL films with Bi₂O₃ loadings ranging from 0 to 300 PHR at different thicknesses were prepared. Radiation attenuation efficiencies (AE) at 60, 80, 100, and 120 kVp were determined and attenuation isocontour curves predicted film thickness and Bi₂O₃ loading required to meet or exceed the radiation attenuation requirements of ASTM D7866 and commercial RAGs. Optimal curing conditions for GNRL/Bi₂O₃ films with 150 PHR Bi₂O₃ were investigated by varying curing temperatures and time from 87 °C to 96 °C and 65 min to 90 min, respectively. In general, as the loading of the filler increased, the density of the films increased while the thickness decreased. GNRL/Bi₂O₃ films with 150 PHR Bi₂O₃ and 0.27 mm provided 5% more AE than RAG market average attenuation at the same thickness. The films with 150 PHR Bi₂O₃ cured under near-optimal conditions (90 °C/85 min, and 87 °C/65 min) met both the radiation attenuation standard (ASTM D7866) and the natural latex surgeon and examination glove standards (ASTM D3577 and D3578, respectively). Thus, gloves made using our formulations and protocols demonstrated potential to meet and surpass medical natural latex glove standards, offer a single product for both infection control and radiation protection instead of double-gloving, provide a greater degree of comfort to the user, and simultaneously reduce contact reactions and eliminate potential latex allergic reaction.

CT Fluoroscopy for Image-Guided Procedures: Physician Radiation Dose During Full-Rotation and Partial-Angle CT Scanning

PURPOSE

To determine physician radiation exposure when using partial-angle computed tomography (CT) fluoroscopy (PACT) vs conventional full-rotation CT and whether there is an optimal tube/detector position at which physician dose is minimized.

MATERIALS AND METHODS

Physician radiation dose (entrance air kerma) was measured for full-rotation CT (360°) and PACT (240°) at all tube/detector positions using a human-mimicking phantom placed in a 64-channel multidetector CT. Parameters included 120 kV, 20- and 40-mm collimation, and 100 mA. The mean, standard deviation, and increase/decrease in physician dose compared with a full-rotation scan were reported.

RESULTS

Physician radiation exposure during CT fluoroscopy with PACT was highly dependent on the position of the tube/detector during scanning. The lowest PACT physician dose was when the physician was on the detector side (center view angle 116°; -35% decreased dose vs full-angle CT). The highest PACT physician dose was with the physician on the tube side (center view angle 298°; +34% increased dose vs full-angle CT), all doses P <.05 vs full-rotation CT.

CONCLUSIONS

Partial-angle CT has the potential to both significantly increase or decrease physician radiation dose during CT fluoroscopy-guided procedures. The detector/tube position has a profound effect on physician dose. The lowest dose during PACT was achieved when the physician was located on the detector side (ie, distant from the tube). This data could be used to optimize CT fluoroscopy parameters to reduce physician radiation exposure for PACT-capable scanners.

The future of interventional and neurointerventional radiology: learning lessons from the past

The rapid progression of medical imaging technology and the ability to leverage knowledge from non-invasive imaging means that Interventional Radiologists (IRs) and Interventional Neuroradiologists are optimally placed to incorporate minimally invasive interventional paradigms into clinical management to advance patient care. There is ample opportunity to radically change the management options for patients with a variety of diseases through the use of minimally invasive interventional procedures. However, this will need to be accompanied by an increased clinical role of IRs to become active partners in the clinical management of patients. Unfortunately, the development of IR clinical presence has lagged behind and is reflected by declining rates of IR involvement in certain areas of practice such as vascular interventions. Current and future IRs must be willing to take on clinical responsibilities; reviewing patients in clinic to determine suitability for a procedure and potential contraindications, rounding on hospital inpatients and be willing to manage procedure related complications, which are all important parts of a successful IR practice. Increasing our clinical presence has several advantages over the procedure-driven model including enhanced patient knowledge and informed consent for IR procedures, improved rapport with patients and other clinical colleagues through active participation and engagement in patient care, visibility as a means to facilitate referrals and consistency of follow-up with opportunities for further learning. Many of the solutions to these problems are already in progress and the use of IR as a "hired gun" or "technician" is a concept that should be relegated to the past, and replaced with recognition of IRs as clinicians and partners in delivering modern high quality multidisciplinary team-based patient care. The following article will review the history of IR, the challenges facing this rapidly evolving profession and discuss recent developments occurring globally that are essential in maintaining expertise, securing future growth and improving patient outcomes in the modern multidisciplinary practice of medicine.

Percutaneous image-guided pelvic procedures in women with gynecologic cancers: utilization, complications, and impact on patient management

PURPOSE

Image-guided percutaneous pelvic procedures often play an important role in the management of women with gynecologic cancers. The purpose of this study is to evaluate the utilization of and indications for these procedures, and quantify their impact on patient management.

METHODS

IRB-approved retrospective record review of percutaneous pelvic procedures requested by gynecologic oncology, 2005 to 2015. Descriptive statistics and logistic regression were performed.

RESULTS

392 pelvic procedures, including fluid aspiration, core biopsy, and fine needle aspiration, were performed in 225 women. Procedures were performed under sonographic guidance (303/392, 77.30%), CT guidance (87/392, 22.19%), or both (2/392, 0.51%). Pathology results included: no specimen sent (157/392, 40.05%), new cancer diagnosis (55/392, 14.03%), recurrence or metastasis of known primary cancer (107/392, 27.30%), benign tissue (67/392, 17.09%), and nondiagnostic (6/392, 1.53%). In terms of management, some procedures led to oncologic surgery, radiation, or chemotherapy (158/392, 40.31%), cessation of oncologic treatment (36/392, 9.18%), or treatment of infection (10/392, 2.55%). Many procedures were therapeutic (178/392, 45.41%), while a minority were performed for genomics (1/392, 0.26%) or did not impact clinical management (9/392, 2.30%). The number of procedures per year increased over time during the period of data collection. Date of service was a significant positive predictor of a purely therapeutic procedure (OR 1.69 [95 % CI 1.44-1.98], p < 0.0001) and a significant negative predictor of a malignant diagnosis (OR 0.72 [95 % CI 0.64-0.81], p < 0.0001), for each year later in the 10-year cycle.

CONCLUSION

In this single institution study, we identified a trend toward increased utilization of image-guided percutaneous pelvic interventions in women with gynecologic cancers. The case mix has shifted over the past 10 years, with procedures for symptom management constituting a larger proportion and diagnostic procedures constituting a smaller proportion of procedures over time.

T2 relaxation time is related to liver fibrosis severity

BACKGROUND

The grading of liver fibrosis relies on liver biopsy. Imaging techniques, including elastography and relaxometric, techniques have had varying success in diagnosing moderate fibrosis. The goal of this study was to determine if there is a relationship between the T2-relaxation time of hepatic parenchyma and the histologic grade of liver fibrosis in patients with hepatitis C undergoing both routine, liver MRI and liver biopsy, and to validate our methodology with phantoms and in a rat model of liver fibrosis.

METHODS

This study is composed of three parts: (I) 123 patients who underwent both routine, clinical liver MRI and biopsy within a 6-month period, between July 1999 and January 2010 were enrolled in a retrospective study. MR imaging was performed at 1.5 T using dual-echo turbo-spin echo equivalent pulse sequence. T2 relaxation time of liver parenchyma in patients was calculated by mono-exponential fit of a region of interest (ROI) within the right lobe correlating to histopathologic grading (Ishak 0-6) and routine serum liver inflammation [aspartate aminotransferase (AST) and alanine aminotransferase (ALT)]. Statistical comparison was performed using ordinary logistic and ordinal logistic regression and ANOVA comparing T2 to Ishak fibrosis without and using AST and ALT as covariates; (II) a phantom was prepared using serial dilutions of dextran coated magnetic iron oxide nanoparticles. T2 weighed imaging was performed by comparing a dual echo fast spin echo sequence to a Carr-Purcell-Meigboom-Gill (CPMG) multi-echo sequence at 1.5 T. Statistical comparison was performed using a paired t-test; (III) male Wistar rats receiving weekly intraperitoneal injections of phosphate buffer solution (PBS) control (n=4 rats); diethylnitrosamine (DEN) for either 5 (n=5 rats) or 8 weeks (n=4 rats) were MR imaged on a Bruker Pharmascan 4.7 T magnet with a home-built bird-cage coil. T2 was quantified by using a mono-exponential fitting algorithm on multi-slice multi echo T2 weighted data. Statistical comparison was performed using ANOVA.

RESULTS

(I) Histopathologic evaluation of both rat and human livers demonstrated no evidence of steatosis or hemochromatosis There was a monotonic increase in mean T2 value with increasing degree of fibrosis (control 65.4±2.9 ms, n=6 patients); mild (Ishak 1-2) 66.7±1.9 ms (n=30); moderate (Ishak 3-4) 71.6±1.7 ms (n=26); severe (Ishak 5-6) 72.4±1.4 ms (n=61); with relatively low standard error (~2.9 ms). There was a statistically significant difference between degrees of mild (Ishak <4) vs. moderate to severe fibrosis (Ishak >4) (P=0.03) based on logistic regression of T2 and Ishak, which became insignificant (P=0.07) when using inflammatory markers as covariates. Expanding on this model using ordinal logistic regression, there was significance amongst all 4 groups comparing T2 to Ishak (P=0.01), with significance using inflammation as a covariate (P=0.03) and approaching statistical significance amongst all groups by ANOVA (P=0.07); (II) there was a monotonic increase in T2 and statistical significance (ANOVA P<0.0001) between each rat subgroup [phosphate buffer solution (PBS) 25.2±0.8, DEN 5-week (31.1±1.5), and DEN 9-week (49.4±0.4) ms]; (III) the phantoms that had T2 values within the relevant range for the human liver (e.g., 20-100 ms), demonstrated no statistical difference between two point fits on turbo spin echo (TSE) data and multi-echo CPMG data (P=0.9).

CONCLUSIONS

The finding of increased T2 with liver fibrosis may relate to inflammation that may be an alternative or adjunct to other noninvasive MR imaging based approaches for assessing liver fibrosis.

Impact of Dose-Modified Protocols on Radiation Doses in Patients Undergoing CT Examinations following Image-Guided Catheter Placement

PURPOSE

To investigate the impact of dose-modified (DM) scan protocols on decreasing radiation exposure from computed tomography (CT) scans obtained following image-guided catheter procedures.

MATERIALS AND METHODS

In this retrospective analysis, between December 2012 and June 2014, 192 patients (mean age, 60.7 y; 102 men) who underwent abdomen/pelvis CT examinations for catheter placement follow-up were included. The standard-dose (SD) baseline CT parameters included tube potential of 120 kVp, tube current of 75-550 mA, and noise index (NI) of 18-22. Weight-based scan parameters applied for follow-up CT were based on two reconstruction algorithms: filtered back projection (FBP; 120 kVp, 75-350 mA, NI = 30) and iterative reconstruction technique (IRT; 100/120 kVp, 75-250/350 mA, NI = 35). Two readers reviewed image quality (IQ) of follow-up and baseline CT examinations for 22 randomly sampled patients. Radiation doses were retrieved by dose monitoring software.

RESULTS

Compared with baseline, DM follow-up CT protocols enabled substantial (62.4%) dose reductions (mean CT dose indexes: 4.1 mGy at follow-up, 10.9 mGy at baseline; P < .0001). Doses were significantly lower for IRT follow-up CT examinations compared with FBP (mean CT dose indexes: IRT, 3.6 mGy; FBP, 4.6 mGy; P < .05). In 47 patients with more than one follow-up CT examination (mean, 3.1 examinations per patient; range, 2-6), the observed cumulative radiation dose (CRD) was 42.1% lower than the expected CRD (observed, 1,437.9 mGy·cm; expected, 2,483.6 mGy·cm; P < .0001). Subjective IQ scores were acceptable for follow-up CT examinations (follow-up, 3.6; baseline, 4; P < .05).

CONCLUSIONS

DM CT examinations enable substantial dose reduction (62.4%) for each follow-up examination compared with SD baseline scans, without any IQ concerns. Use of IRT decreases dose by an additional 22%. The CRD is lowered by 42% in patients undergoing multiple DM follow-up CT examinations.