Interventional radiology in the chest and abdomen

Part 2: Current Concepts in Radiologic Imaging & Intervention in Acute Biliary Tract Diseases

Acute cholangitis is encountered commonly in critically ill, often elderly, patients. The most common causes of cholangitis include choledocholithiasis, biliary strictures, and infection from previous endoscopic, percutaneous, or surgical intervention of the biliary tract. Rare causes of acute cholangitis in the United States include sclerosing cholangitis and recurrent pyogenic cholangitis, the latter predominantly occurring in immigrants of Asian descent. Multidisciplinary management of these conditions is essential, with intensivists, surgeons, diagnostic radiologists, interventional radiologists, gastroenterologists, endoscopists, and infectious disease physicians typically involved in the care of these patients. In this paper intended for intensivists predominantly, we will review the imaging findings and radiologic interventional management of critically ill patients with acute cholangitis, primary and secondary sclerosing cholangitis, and recurrent pyogenic cholangitis.

Part 1: Current Concepts in Radiologic Imaging and Intervention in Acute Cholecystitis

Acute calculous cholecystitis and acute acalculous cholecystitis are encountered commonly among critically ill, often elderly, patients. Multidisciplinary management of these conditions is essential, with intensivists, surgeons, diagnostic radiologists, interventional radiologists, infectious disease physicians, gastroenterologists, and endoscopists able to contribute to patient care. In this article intended predominantly for intensivists, we will review the imaging findings and radiologic treatment of critically ill patients with acute calculous cholecystitis and acute acalculous cholecystitis.

Risk Factors for Pneumothorax Development Following CT-Guided Core Lung Nodule Biopsy

BACKGROUND

This study aims to correlate nodule, patient, and technical risk factors less commonly investigated in the literature with pneumothorax development during computed tomography-guided core needle lung nodule biopsy.

PATIENTS AND METHODS

Retrospective data on 671 computed tomography-guided percutaneous core needle lung biopsies from 671 patients at a tertiary care center between March 2014 and August 2016. Univariate and multivariable logistic regression analyses were used to identify pneumothorax risk factors.

RESULTS

The overall incidence of pneumothorax was 26.7% (n=179). Risk factors identified on univariate analysis include anterior [odds ratio (OR)=1.98; P<0.001] and lateral (OR=2.17; P=0.002) pleural surface puncture relative to posterior puncture, traversing more than one pleural surface with the biopsy needle (OR=2.35; P=0.06), patient positioning in supine (OR=2.01; P<0.001) and decubitus nodule side up (OR=2.54; P=0.001) orientation relative to decubitus nodule side down positioning, and presence of emphysema in the path of the biopsy needle (OR=3.32; P<0.001). In the multivariable analysis, the presence of emphysematous parenchyma in the path of the biopsy needle was correlated most strongly with increased odds of pneumothorax development (OR=3.03; P=0.0004). Increased body mass index (OR=0.95; P=0.001) and larger nodule width (cm; OR=0.74; P=0.02) were protective factors most strongly correlated with decreased odds of pneumothorax development.

CONCLUSION

Emphysema in the needle biopsy path is most strongly associated with pneumothorax development. Increases in patient body mass index and width of the target lung nodule are most strongly associated with decreased odds of pneumothorax.

Determination of a tactile feedback strategy for use in robotized percutaneous procedures

Remote manipulation in robotized percutaneous procedures can offer increased safety to radiologists as well as patients. Providing feedback to the radiologist on needle-tissue interactions is however mandatory in addition to the medical images. A tactile feedback strategy is developed in this paper. Two types of information are considered: tissue puncture and nature of tissues. A haptic device is developed for that purpose, using a tactile display to provide information. Adequate signals are identified experimentally, with analysis of reaction times and the ability to discriminate one information from the other.

A Novel Translational Ovine Pulmonary Adenocarcinoma Model for Human Lung Cancer

In vitro cell line and in vivo murine models have historically dominated pre-clinical cancer research. These models can be expensive and time consuming and lead to only a small percentage of anti-cancer drugs gaining a license for human use. Large animal models that reflect human disease have high translational value; these can be used to overcome current pre-clinical research limitations through the integration of drug development techniques with surgical procedures and anesthetic protocols, along with emerging fields such as implantable medical devices. Ovine pulmonary adenocarcinoma (OPA) is a naturally-occurring lung cancer that is caused by the jaagsiekte sheep retrovirus. The disease has similar histological classification and oncogenic pathway activation to that of human lung adenocarcinomas making it a valuable model for studying human lung cancer. Developing OPA models to include techniques used in the treatment of human lung cancer would enhance its translational potential, making it an excellent research tool in assessing cancer therapeutics. In this study we developed a novel OPA model to validate the ability of miniaturized implantable O₂ and pH sensors to monitor the tumor microenvironment. Naturally-occurring pre-clinical OPA cases were obtained through an on-farm ultrasound screening programme. Sensors were implanted into OPA tumors of anesthetized sheep using a CT-guided trans-thoracic percutaneous implantation procedure. This study reports the findings from 9 sheep that received sensor implantations. Time taken from initial CT scans to the placement of a single sensor into an OPA tumor was 45 ± 5 min, with all implantations resulting in the successful delivery of sensors into tumors. Immediate post-implantation mild pneumothoraces occurred in 4 sheep, which was successfully managed in all cases. This is, to the best of our knowledge, the first description of the use of naturally-occurring OPA cases as a pre-clinical surgical model. Through the integration of techniques used in the treatment of human lung cancer patients, including ultrasound, general anesthesia, CT and surgery into the OPA model, we have demonstrated its translational potential. Although our research was tailored specifically for the implantation of sensors into lung tumors, we believe the model could also be developed for other pre-clinical applications.

Observations And Experiments For The Definition Of A New Robotic Device Dedicated To CT, CBCT And MRI-Guided Percutaneous Procedures

In this paper, we present the work achieved to define the robotic functionalities of interest for percutaneous procedures as performed in interventional radiology. Our contributions are twofold. First, a detailed task analysis is performed with workflow analysis of biopsies, one of the most frequent tasks, under three imaging modalities, namely CT, CBCT and MRI. Second, the functionalities of a robotic assistant are identified, and we analyze whether a single device can bring an added value during procedures in the three modalities while keeping the robotized workflow close to manual tasks, to minimize learning time and difficulty of use. Experimental analysis on CBCT is notably used to confirm the interest of the determined robotic functionalities.

Image-guided percutaneous drainage: a review

Percutaneous abscess drainage (PAD) has been proven to be a safe, effective, and widely used technique for treatment of patients with intra-abdominal fluid collections. Indications for PAD are ever expanding, and most abscesses are amenable to PAD. PAD is routinely used for treatment of simple unilocular abscesses however more complex collections require a collaborative strategy with surgical services for patient management. PAD is also used as a temporizing procedure for patients who will ultimately require operative intervention. A variety of imaging modalities are used for PAD including ultrasound and CT. Several catheter insertion techniques have proven effective. Complications from PAD are relatively uncommon.

Interventional radiology: a half century of innovation

The evolution of modern interventional radiology began over half century ago with a simple question. Was it possible to use the same diagnostic imaging tools that had revolutionized the practice of medicine to guide the real-time treatment of disease? This disruptive concept led to rapid treatment advances in every organ system of the body. It became clear that by utilizing imaging some patients could undergo targeted procedures, eliminating the need for major surgery, while others could undergo procedures for previously unsolvable problems. The breadth of these changes now encompasses all of medicine and has forever changed the way we think about disease. In this brief review article, major advances in the field, as chronicled in the pages of Radiology, will be described.

Evaluation of an electromagnetic image-fusion navigation system for biopsy of small lesions: assessment of accuracy in an in vivo swine model

PURPOSE

To evaluate the accuracy of a novel combined electromagnetic (EM) navigation/image fusion system for biopsy of small lesions.

MATERIALS AND METHODS

Using ultrasound (US) guidance, metallic (2 × 1 mm) targets were imbedded in the paraspinal muscle (n = 28), kidney (n = 18), and liver (n = 4) of four 55- to 65-kg pigs. Baseline helical computed tomography (CT) imaging (Brilliance; Philips) identified these biopsy targets and six and nine cutaneous fiducial markers. CT data were imported into a MyLab Twice system (Esaote, Genoa, Italy) for CT/US image fusion. After verification of successful image fusion, baseline registration error and respiratory motion error were assessed by documenting deviation of the US and CT position of the targets in real time. Biopsy targeting was subsequently performed under conditions of normal respiratory using 15-cm 16G eTrax needles (Civco). To mimic the conditions of poor US visualization, only reconstructed CT information was displayed during biopsy. Accuracy of targeting was measured by repeat CT scanning as the distance of the needle tip to the target center. Targeting accuracy of free-hand vs. guided technique, and electromagnetic (EM) sensor positioning (ie, on the hub or within the needle stylus tip) were evaluated.

RESULTS

In muscle, needle registration error was 0.9 ± 1.2 mm and respiratory motion error 4.0 ± 1.0 mm. Target accuracy was 4.0 ± 3.2 mm when an EM sensor was imbedded in the needle tip. Yet, with the EM sensor back on the needle hub, greater targeting accuracy was achieved using an US guide (3.2 ± 1.6 mm) vs. freehand (5.7 ± 3.2 mm, P = .04). For kidney, registration error was 1.8 ± 1.7 mm and respiratory motion error 4.9 ± 1.0 mm. For the deeper kidney targets, target accuracy was 4.4 ± 3.2 mm with a tip EM sensor, which was an improvement over the hub EM sensor positioning (9.3 ± 4.6 mm; P < .01). An additional source of fusion error was noted for liver. Beyond 17 ± 1 mm of respiratory motion, targets were observed to move >3 cm with US transducer/needle compression resulting in 14 ± 1.4 mm targeting accuracy.

CONCLUSIONS

A combined image-fusion/EM tracking platform can provide a high degree of needle placement accuracy (<5 mm) when targeting small lesions. Results fall within accuracy of respiratory error; with best results obtained by incorporating an EM sensor into the tip of the biopsy system.

Transthoracic needle biopsy

Transthoracic needle biopsy (TTNB) is integral in the diagnosis and treatment of many thoracic diseases, and is an important alternative to more invasive surgical procedures. Both computed tomography and ultrasound may be used as imaging guidance for TTNB, with CT being more commonly utilized. Needle choice depends mostly upon lesion characteristics and location. During the procedure, patients must be able to follow breathing instructions. Common complications of TTNB include pneumothorax and hemoptysis.

Electromagnetic navigation system for CT-guided biopsy of small lesions

OBJECTIVE

The purpose of this study was to evaluate an electromagnetic navigation system for CT-guided biopsy of small lesions.

MATERIALS AND METHODS

Standardized CT anthropomorphic phantoms were biopsied by two attending radiologists. CT scans of the phantom and surface electromagnetic fiducial markers were imported into the memory of the 3D electromagnetic navigation system. Each radiologist assessed the accuracy of biopsy using electromagnetic navigation alone by targeting sets of nine lesions (size range, 8-14 mm; skin to target distance, 5.7-12.8 cm) under eight different conditions of detector field strength and orientation (n = 117). As a control, each radiologist also biopsied two sets of five targets using conventional CT-guided technique. Biopsy accuracy, number of needle passes, procedure time, and radiation dose were compared.

RESULTS

Under optimal conditions (phantom perpendicular to the electromagnetic receiver at highest possible field strength), phantom accuracy to the center of the lesion was 2.6 ± 1.1 mm. This translated into hitting 84.4% (38/45) of targets in a single pass (1.1 ± 0.4 CT confirmations), which was significantly fewer than the 3.6 ± 1.3 CT checks required for conventional technique (p < 0.001). The mean targeting time was 38.8 ± 18.2 seconds per lesion. Including procedural planning (∼5.5 minutes) and final CT confirmation of placement (∼3.5 minutes), the full electromagnetic tracking procedure required significantly less time (551.6 ± 87.4 seconds [∼9 minutes]) than conventional CT (833.3 ± 283.8 seconds [∼14 minutes]) for successful targeting (p < 0.001). Less favorable conditions, including nonperpendicular relation between the axis of the machine and weaker field strength, resulted in statistically significant lower accuracy (3.7 ± 1 mm, p < 0.001). Nevertheless, first-pass biopsy accuracy was 58.3% (21/36) and second-pass (35/36) accuracy was 97.2%. Lesions farther from the skin than 20-25 cm were out of range for successful electromagnetic tracking.

CONCLUSION

Virtual electromagnetic tracking appears to have high accuracy in needle placement, potentially reducing time and radiation exposure compared with those of conventional CT techniques in the biopsy of small lesions.

Micro-NMR for rapid molecular analysis of human tumor samples

Although tumor cells obtained from human patients by image-guided intervention are a valuable source for diagnosing cancer, conventional means of analysis are limited. Here, we report the development of a quantitative micro-NMR (nuclear magnetic resonance) system for rapid, multiplexed analysis of human tumors. We implemented the technology in a clinical setting to analyze cells obtained by fine-needle aspirates from suspected lesions in 50 patients and validated the results in an independent cohort of another 20 patients. Single fine-needle aspirates yielded sufficient numbers of cells to enable quantification of multiple protein markers in all patients within 60 min. Moreover, using a four-protein signature, we report a 96% accuracy for establishing a cancer diagnosis, surpassing conventional clinical analyses by immunohistochemistry. Our results also show that protein expression patterns decay with time, underscoring the need for rapid sampling and diagnosis close to the patient bedside. We also observed a surprising degree of heterogeneity in protein expression both across the different patient samples and even within the same tumor, which has important implications for molecular diagnostics and therapeutic drug targeting. Our quantitative point-of-care micro-NMR technique shows potential for cancer diagnosis in the clinic.

CT-guided percutaneous cutting needle biopsy of thymic epithelial tumors comparison to the accuracy of computed tomographic diagnosis according to the world health organization classification

RATIONALE AND OBJECTIVES

The aims of this study were to compare diagnostic accuracy between computed tomography (CT)-guided percutaneous cutting needle biopsy (PCNB) and surgery or open biopsy for thymic epithelial tumors in accordance with the World Health Organization (WHO) classification and to evaluate computed tomographic diagnosis additionally.

MATERIALS AND METHODS

Subjects were 20 patients (11 men, 9 women) in whom CT, CT-guided PCNB, and surgery had been performed for anterior mediastinal tumors. All diagnoses of both CT-guided PCNB and surgery or open biopsy were made in accordance with the WHO classification. Computed tomographic diagnoses were performed by two radiologists on the basis of radiologic characteristics previously reported according to the simplified WHO classification (types A and AB, type B1, types B2 and B3, and thymic carcinoma). The concordance of the WHO classification or the simplified WHO classification between the diagnosis on either CT or CT-guided PCNB and that on surgery was evaluated using the weighted kappa statistic.

RESULTS

The histologic classifications on the basis of surgical resection specimens were as follows: type A, n = 3; type AB, n = 5; type B1, n = 3; type B2, n = 4; type B3, n = 4; and thymic carcinoma, n = 1. The overall concordance with the diagnosis according to the WHO classification established using CT-guided PCNB specimens (weighted kappa = 0.757) was higher than that using computed tomographic diagnosis (weighted kappa = 0.437).

CONCLUSION

CT-guided PCNB is a technique with good concordance of the WHO classification of thymic epithelial tumors between the diagnoses of surgery or open biopsy.

CT fluoroscopy-guided lung biopsy with novel steerable biopsy canula: ex-vivo evaluation in ventilated porcine lung explants

The purpose was to evaluate ex-vivo a prototype of a novel biopsy canula under CT fluoroscopy-guidance in ventilated porcine lung explants in respiratory motion simulations. Using an established chest phantom for porcine lung explants, n = 24 artificial lesions consisting of a fat-wax-Lipiodol mixture (approx. 70HU) were placed adjacent to sensible structures such as aorta, pericardium, diaphragm, bronchus and pulmonary artery. A piston pump connected to a reservoir beneath a flexible silicone reconstruction of a diaphragm simulated respiratory motion by rhythmic inflation and deflation of 1.5 L water. As biopsy device an 18-gauge prototype biopsy canula with a lancet-like, helically bended cutting edge was used. The artificial lesions were punctured under CT fluoroscopy-guidance (SOMATOM Sensation 64, Siemens, Erlangen, Germany; 30mAs/120 kV/5 mm slice thickness) implementing a dedicated protocol for CT fluoroscopy-guided lung biopsy. The mean-diameter of the artificial lesions was 8.3 +/- 2.6 mm, and the mean-distance of the phantom wall to the lesions was 54.1 +/- 13.5 mm. The mean-displacement of the lesions by respiratory motion was 14.1 +/- 4.0 mm. The mean-duration of CT fluoroscopy was 9.6 +/- 5.1 s. On a 4-point scale (1 = central; 2 = peripheral; 3 = marginal; 4 = off target), the mean-targeted precision was 1.9 +/- 0.9. No misplacement of the biopsy canula affecting adjacent structures could be detected. The novel steerable biopsy canula proved to be efficient in the ex-vivo set-up. The chest phantom enabling respiratory motion and the steerable biopsy canula offer a feasible ex-vivo system for evaluating and training CT fluoroscopy-guided lung biopsy adapted to respiratory motion.

[Flat-detector CT-based electromagnetic navigation]

Flat-detector CT coupled to an angiography device provides an imaging technique for interventions which can be used for electromagnetically navigated percutaneous punctures. This report explains the functionality of an electromagnetic navigation system and describes the course of an electromagnetically navigated puncture and the capabilities of such a system in the clinical routine.

Cigarette smoke exposure promotes arterial thrombosis and vessel remodeling after vascular injury in apolipoprotein E-deficient mice

BACKGROUND

Cigarette smoking is a major risk factor for the development of cardiovascular disease. However, in terms of the vessel wall, the underlying pathomechanisms of cigarette smoking are incompletely understood, partly due to a lack of adequate in vivo models.

METHODS

Apolipoprotein E-deficient mice were exposed to filtered air (sham) or to cigarette mainstream smoke at a total particulate matter (TPM) concentration of 600 microg/l for 1, 2, 3, or 4 h, for 5 days/week. After exposure for 10 +/- 1 weeks, arterial thrombosis and neointima formation at the carotid artery were induced using 10% ferric chloride.

RESULTS

Mice exposed to mainstream smoke exhibited shortened time to thrombotic occlusion (p < 0.01) and lower vascular patency rates (p < 0.001). Morphometric and immunohistochemical analysis of neointimal lesions demonstrated that mainstream smoke exposure increased the amount of alpha-actin-positive smooth muscle cells (p < 0.05) and dose-dependently increased the intima-to-media ratio (p < 0.05). Additional analysis of smooth muscle cells in vitro suggested that 10 microg TPM/ml increased cell proliferation without affecting viability or apoptosis, whereas higher concentrations (100 and 500 microg TPM/ml) appeared to be cytotoxic.

CONCLUSIONS

Taken together, these findings suggest that cigarette smoking promotes arterial thrombosis and modulates the size and composition of neointimal lesions after arterial injury in apolipoprotein E-deficient mice.

CT Fluoroscopy–guided Biopsy of Small Pulmonary and Upper Abdominal Lesions: Efficacy with a Modified Breathing Technique

PURPOSE

To characterize a new protocol of computed tomographic (CT) fluoroscopy-guided biopsy of the lung and upper abdomen to minimize the intervention time, complication rate, and exposure to ionizing radiation for both the patient and the radiologist.

MATERIALS AND METHODS

Fifty patients (23 women, 27 men; mean age, 64.3 years; age range, 36-83 years) with lung (n = 41) or upper abdomen (n = 9) nodules 15 mm or smaller underwent CT fluoroscopy-guided biopsy from November 2005 to October 2006. The mean nodule diameter was 12.6 mm (range, 8-15 mm), the mean depth to skin was 57.3 mm (range, 20-114 mm), and the mean depth of nodules from pleura and/or peritoneum was 18.9 mm (range, 1-77 mm). Histopathologic evaluation of samples was performed on the day of the procedure. A CT fluoroscopy-guided biopsy protocol was established as follows: (a) native CT with breath-holding at an intermediate respiration level, (b) selection of section position with target nodule and insertion of an 18-gauge coaxial biopsy needle extrapleurally and/or extraperitoneally virtually targeting at nodule, (c) start of CT fluoroscopy (130 kVp, 30 mAs, 5-mm-thick sections) at inspiration level with the patient expiring, (d) stop of CT fluoroscopy when the target nodule reaches the section position, short breath-hold, needle advancement to the target nodule, (e) control of needle position with CT fluoroscopy, and (f) biopsy.

RESULTS

The mean total table time was 23.8 minutes (range, 15-41 minutes), the mean duration of CT fluoroscopy was 8.2 seconds (range, 4-23 seconds), and the mean duration of breath-holding--including needle insertion to target nodule and control CT fluoroscopy--was 10.3 seconds (range, 5-15 seconds). There were three minor pneumothoraces that required no further intervention, seven minor pulmonary hemorrhages, three moderate pulmonary hemorrhages with hemoptysis, and one moderate liver hematoma. There were no major complications. The diagnostic accuracy of biopsy samples was 96%.

CONCLUSIONS

The presented modification of CT fluoroscopy-guided biopsy of mobile pulmonary and upper abdominal lesions is a rapid and safe procedure, requiring only short exposure to ionizing radiation.

Computed tomography-guided percutaneous abscess drainage in coloproctology: review of the literature

BACKGROUND

Percutaneous abscess drainage (PAD) of the lower abdomen and pelvis has been reported to reduce morbidity and mortality, shorten hospital stay and cut costs compared to a surgical approach. However, the wide differences in outcome reported by different authors indicate the need for an overview and further evaluations. This review evaluates each point of the procedure to explain the possible causes for such discrepancies in results.

METHODS

We performed a PubMed search of outcomes for percutaneous abscesses drainage, focusing on deep pelvic collections, which represent the most difficult task, searching among papers published from 1981 to 2006.

RESULTS

Ninety-nine papers were selected. Most authors emphasized that the most important steps of the care process are: (a) patient selection; (b) indications and contraindications; (c) choice of the best access route; (d) procedure performance; and (e) outcome (success and complication rates).

CONCLUSIONS

PAD is a safe and effective alternative to surgery for draining deep infected fluid collections, with a higher success rate, lower complication rate and shorter hospital stay compared to surgical drainage. Meticulous technique and careful access planning seem to be the two most important factors affecting the outcome.

CT fluoroscopy shielding: decreases in scattered radiation for the patient and operator

PURPOSE

High-radiation exposure occurs during computed tomographic (CT) fluoroscopy. Patient and operator doses during thoracic and abdominal interventional procedures were studied in the present experiment, and a novel shielding device to reduce exposure to the patient and operator was evaluated.

MATERIALS AND METHODS

With a 16-slice CT scanner in CT fluoroscopy mode (120 kVp, 30 mA), surface dosimetry was performed on adult and pediatric phantoms. The shielding was composed of tungsten antimony in the form of a lightweight polymer sheet. Doses to the patient were measured with and without shielding for thoracic and abdominal procedures. Doses to the operator were recorded with and without phantom, gantry, and table shielding in place. Double-layer lead-free gloves were used by the operator during the procedures.

RESULTS

Tungsten antimony shielding adjacent to the scan plane resulted in a maximum dose reduction of 92.3% to the patient. Maximum 85.6%, 93.3%, and 85.1% dose reductions were observed for the operator's torso, gonads, and hands, respectively. The use of double-layer lead-free gloves resulted in a maximum radiation dose reduction of 97%.

CONCLUSIONS

Methods to reduce exposure during CT fluoroscopy are effective and should be searched for. Significant reduction in radiation doses to the patient and operator can be accomplished with tungsten antimony shielding.

Diagnostic accuracy of CT-guided percutaneous cutting needle biopsy for thymic tumours

AIM

To determine the diagnostic accuracy of computed tomography (CT)-guided percutaneous cutting needle biopsy (PCNB) for thymic tumours in accordance with the World Health Organization (WHO) classification.

MATERIAL AND METHODS

We retrospectively analysed a consecutive series of 138 cases in which CT-guided PCNB had been performed for an anterior mediastinal tumour. Its sensitivity and specificity for thymic epithelial tumours were evaluated, and the concordance between the histopathological diagnosis according to the WHO classification of thymic tumours based on PCNB and the diagnosis is based on the surgical specimens was assessed by Kappa statistic.

RESULTS

The diagnostic sensitivity and specificity of CT-guided PCNB for thymic tumours were 93.3 and 100%, respectively. The overall concordance between the diagnosis according to the WHO classification established by PCNB specimen and by the surgical specimen was 79.4% (weighted kappa=0.79).

CONCLUSION

CT-guided PCNB is a reliable method of diagnosing thymic tumours, and there was good concordance for the WHO classification between the diagnosis based on CT-guided PCNB specimen and that based on the surgical specimen.

Augmented Reality Visualization for CT-guided Interventions: System Description, Feasibility, and Initial Evaluation in an Abdominal Phantom

The purpose of this study was to evaluate the feasibility and performance of an augmented reality (AR) visualization prototype for virtual computed tomography (CT)-guided interventional procedures in a multimodality abdominal phantom. With the aid of AR guidance, three radiologists performed 30 attempts at targeting simulated liver lesions of different sizes (range, 5-15 mm) with a biopsy needle. The position of the needle tip relative to the lesion was verified by using ultrasonography and CT. With AR guidance, lesions were successfully targeted with the first needle pass in all cases. On the basis of these results, AR visualization for CT-guided intervention appears feasible and allows intuitive and accurate lesion targeting in a phantom.

SUPPLEMENTAL MATERIAL

radiology.rsnajnls.org/cgi/content/full/2401040018/DC1

Centromere DNA, proteins and kinetochore assembly in vertebrate cells

The centromere is a specialized region of the chromosome that is essential for faithful chromosome segregation during mitosis and meiosis in eukaryotic cells. It is the site at which the kinetochore, the functional nucleoprotein complex responsible for microtubule binding and chromosome movement, is assembled through complex molecular mechanisms. Herein, I review recent advances in our understanding of centromeric DNAs as sites for kinetochore assembly and the mechanisms underlying kinetochore assembly in vertebrate cells.

Usefulness of Core Roll Preparations in Immediate Assessment of Neoplastic Lung Lesions

INTRODUCTION

CT scan-guided fine-needle aspiration (FNA) of lung nodules is a well-established diagnostic technique. In our institution, both FNA and tissue core biopsy (using a 20-gauge needle) under CT scan guidance are routinely performed during the same procedure, and a preliminary diagnosis (an immediate assessment) is rendered. We compared core roll preparations (CRPs) with aspirate smears in the immediate assessment of pulmonary lesions and also assessed whether CRP resulted in the alteration of the histopathology of the core biopsy.

STUDY DESIGN

Twenty-five cases of neoplastic pulmonary lesions diagnosed in CT scan-guided lung FNA specimens, with core biopsies performed sequentially at the same visit for each patient, were evaluated. CRPs were made by lightly rolling the tissue core on a glass slide, followed by air-drying. Only stained slides (Diff-Quik; Mercedes Medical; Sarasota, FL) were reviewed, and were scored for cellularity and morphology.

RESULTS

CRPs in seven cases (28%) scored more diagnostic points than FNA smears, and were found to be better for cellularity and morphology compared to the corresponding FNA smears. The FNA smears scored more than CRPs in 10 cases (40%), while in 8 cases (32%) both CRPs and FNA smears scored equal diagnostic points. Using both CRP and FNA smears in the immediate assessment of lung biopsy specimens, we could assign a specific malignant histologic cell type in 23 of 25 cases (92%). In comparison, if the FNA smears were evaluated alone, we could assign a specific malignant histologic cell type in only 16 of 25 cases (64%). The CRP did not alter the histopathology of the core biopsy specimens in any of the above cases.

CONCLUSION

The CRP complements the CT scan-guided lung FNA procedure in the immediate assessment of neoplastic lung lesions without altering the histopathology of core biopsy specimens.

Multiinstitutional computer database for recording nonvascular imaging-guided interventions

OBJECTIVE

We sought to describe a multiinstitutional database created for tracking CT and sonographically guided interventional procedures.

CONCLUSION

The database, created using commercially available software, has been placed on the secure hospital internal network for easy access from two institutions. More than 1,000 separate interventions have been added. The data may be queried and filtered for quality assurance and research purposes.

CT arthrography of the glenohumeral joint: CT fluoroscopy versus conventional CT and fluoroscopy--comparison of image-guidance techniques

PURPOSE

To compare examination time with radiologist time and to measure radiation dose of computed tomographic (CT) fluoroscopy, conventional CT, and conventional fluoroscopy as guiding modalities for shoulder CT arthrography.

MATERIALS AND METHODS

Glenohumeral injection of contrast material for CT arthrography was performed in 64 consecutive patients (mean age, 32 years; age range, 16-74 years) and was guided with CT fluoroscopy (n = 28), conventional CT (n = 14), or conventional fluoroscopy (n = 22). Room times (arthrography, room change, CT, and total examination times) and radiologist times (time the radiologist spent in the fluoroscopy or CT room) were measured. One-way analysis of variance and Bonferroni-Dunn posthoc tests were performed for comparison of mean times. Mean effective radiation dose was calculated for each method with examination data, phantom measurements, and standard software.

RESULTS

Mean total examination time was 28.0 minutes for CT fluoroscopy, 28.6 minutes for conventional CT, and 29.4 minutes for conventional fluoroscopy; mean radiologist time was 9.9 minutes, 10.5 minutes, and 9.0 minutes, respectively. These differences were not statistically significant. Mean effective radiation dose was 0.0015 mSv for conventional fluoroscopy (mean, nine sections), 0.22 mSv for CT fluoroscopy (120 kV; 50 mA; mean, 15 sections), and 0.96 mSv for conventional CT (140 kV; 240 mA; mean, six sections). Effective radiation dose can be reduced to 0.18 mSv for conventional CT by changing imaging parameters to 120 kV and 100 mA. Mean effective radiation dose of the diagnostic CT arthrographic examination (140 kV; 240 mA; mean, 25 sections) was 2.4 mSv.

CONCLUSION

CT fluoroscopy and conventional CT are valuable alternative modalities for glenohumeral CT arthrography, as examination and radiologist times are not significantly different. CT guidance requires a greater radiation dose than does conventional fluoroscopy, but with adequate parameters CT guidance constitutes approximately 8% of the radiation dose.

CT fluoroscopy--guided interventional procedures: techniques and radiation dose to radiologists

PURPOSE

To determine the radiation dose to radiologists who perform computed tomographic (CT) fluoroscopic interventional procedures by using a quick-check method and a low-milliampere technique.

MATERIALS AND METHODS

Two hundred twenty CT fluoroscopy--guided interventional procedures were performed in 189 patients. Procedures included 57 spinal injections, 17 spinal biopsies, 24 chest biopsies, 20 abdominal aspirations, 44 abdominal biopsies, and 58 abdominal drainages. Procedure details were prospectively recorded and included site, depth, target diameter, milliampere value, kilovolt peak, fluoroscopic time, and CT technique (continuous CT fluoroscopy, quick-check method, or a combination of these techniques). An individual collar and finger radiation detector were worn by each radiologist during each procedure to determine the dose per procedure.

RESULTS

The quick-check technique was performed in 191 (87%) of 220 procedures. Four procedures were performed with continuous CT fluoroscopy, and a combination technique was used for 25 (11%) procedures. The overall mean CT fluoroscopic time was 17.9 seconds (range, 1.2--101.5 seconds). The mean milliampere value was 13.2 mA (range, 10--50 mA). The overall mean radiologist radiation dose per procedure was 2.5 mrem (0.025 mSv) (whole body). Individual procedure doses ranged from 0.66 to 4.75 mrem (0.007--0.048 mSv). The finger radiation dose was negligible.

CONCLUSION

By using a low-milliampere technique and the quick-check method, CT fluoroscopic time and radiation exposure can be minimized.

Patient and personnel exposure during CT fluoroscopy-guided interventional procedures

PURPOSE

To estimate patient dose and personnel exposure from phantom measurements during computed tomographic (CT) fluoroscopy, to use the estimates to provide users with dose information, and to recommend methods to reduce exposure.

MATERIALS AND METHODS

Surface dose was estimated on a CT dosimetric phantom by using thermoluminescent dosimetric (TLD) and CT pencil chamber measurements. Scatter exposure was estimated from scattered radiation measured at distances of 10 cm to 1 m from the phantom. Scatter exposures measured with and without placement of a lead drape on the phantom surface adjacent to the scanning plane were compared.

RESULTS

Phantom surface dose rates ranged from 2.3 to 10. 4 mGy/sec. Scattered exposure rates for a commonly used CT fluoroscopic technique (120 kVp, 50 mA, 10-mm section thickness) were 27 and 1.2 microGy/sec at 10 cm and 1 m, respectively, from the phantom. Lead drapes reduced the scattered exposure by approximately 71% and 14% at distances of 10 and 60 cm from the scanning plane, respectively.

CONCLUSION

High exposures to patients and personnel may occur during CT fluoroscopy-guided interventions. Radiation exposure to patients and personnel may be reduced by modifying CT scanning techniques and by limiting fluoroscopic time. In addition, scatter exposure to personnel may be substantially reduced by placing a lead drape adjacent to the scanning plane.

Use of fibrin sealant as a hemostatic agent after liver biopsy in swine

PURPOSE

To determine whether fibrin sealant injected into the tract created by liver biopsy can be used to decrease postprocedural bleeding. An innovative delivery system was used to deploy the fibrin sealant.

MATERIALS AND METHODS

Fibrin sealant is a hemostatic agent consisting of a suspension of fibrinogen and thrombin. A delivery system was devised whereby fibrin sealant could be injected into the tract created by liver biopsy. Thirty swine were randomized into three groups: control (n = 10), heparin (n = 10), and warfarin (n = 10). Each swine underwent laparotomy and was randomized to undergo three to five open liver biopsies with either a 14-gauge cutting needle in conjunction with the fibrin sealant device or a standard 14-gauge cutting needle alone. Forty-seven biopsy procedures were performed with the device; 64 biopsy procedures were performed without the device. Immediate blood loss per biopsy (mL) was estimated based on the size of the blood stain on a sponge. Specimens were assessed for sample size.

RESULTS

Immediate blood loss with and without the device, respectively, was: control, 0.1 mL, 5.4 mL; heparin, 0 mL, 7 mL; warfarin, 0.1 mL, 9.3 mL. These differences were significant (P < .01) for each group of swine. In 43 of 47 biopsies (91%), the device functioned without difficulty. There was no difference in sample size when the device was used.

CONCLUSIONS

The fibrin sealant device is effective in reducing bleeding after open liver biopsy in anticoagulated and nonanticoagulated swine. The promising results suggest that a trial of percutaneous liver biopsy in swine should be considered.

Benign pleural diseases

The pleural space is a potential space under normal physiologic circumstances. It envelops the lung, the mediastinum, the diaphragm and the chest wall. A thin film of pleural fluid provides lubrication for the two pleural layers; only 2-10 ml of pleural fluid is present in healthy people. For the purposes of this review, pleural abnormalities will be divided into pleural effusion, pneumothorax, and pleural calcification.

Bedside diagnostic ultrasound and therapeutic ultrasound-guided procedures in the intensive care setting

The availability, portability, safety, and other features of ultrasound have ushered this relatively new imaging modality into the everyday clinical practice of multiple disciplines. Features unique to ultrasound lend this imaging modality the opportunity for extensive use in the ICU. A review of its uses in this capacity includes bedside diagnosis of common disorders seen in the ICU setting, such as DVT, cholecystitis, and abscess. Bedside sonography also can aid in the treatment of such disorders, including DGC of pseudoaneurysms, fluid aspirations, and abscess drainages. This article is a review and could not possibly cover all bedside uses of ultrasound or provide in-depth information of specific uses described in this article. Hopefully, this article will spark an interest and prove as a starting point on a rewarding learning adventure.

CT fluoroscopy-guided abdominal interventions: techniques, results, and radiation exposure

PURPOSE

To evaluate the benefits of computed tomographic (CT) fluoroscopy-guided interventions and assess radiation exposures incurred with CT fluoroscopy.

MATERIALS AND METHODS

A 6-month period of use of CT fluoroscopy to guide abdominal biopsy procedures and catheter drainage was analyzed. Efficacy measures and needle placement and procedure room times were compared with those of the preceding 6 months during which conventional CT was used. CT fluoroscopic times and estimated radiation exposures were compared for two CT fluoroscopic methods.

RESULTS

The sensitivity and negative predictive values for biopsy procedures and the success rate for needle aspiration or catheter drainages for CT fluoroscopy--98%, 86%, and 100%, respectively--were not significantly different from those for conventional CT--95%, 80%, and 97%, respectively. Room time was not reduced significantly, but mean needle placement time for CT fluoroscopy (29 minutes; n = 95) was significantly lower than that for conventional CT (36 minutes; n = 93; P < .005). The mean patient dose index was 74 cGy. Limiting CT fluoroscopy to scanning the needle tip rather than scanning the entire needle pass significantly reduced the dose to the patient and the operator.

CONCLUSION

Although CT fluoroscopy is a useful targeting technique, significant radiation exposures may result. Therefore, radiologists need to be aware of different methods of CT fluoroscopic guidance and the factors that contribute to radiation exposure.

Open-configuration MR imaging, intervention, and surgery of the urinary tract

The open-configuration MR imaging system provides new applications both in diagnosis and in therapy of conditions in the urinary tract. In addition to conventional imaging, the open configuration permits MR imaging of patients in many positions. This has already been shown to be useful in imaging the pelvis during voiding, where a sitting position allows urodynamic evaluation. The lithotomy position can be used for imaging the prostate, which also permits procedural access. The ultimate purpose of the interventional MR imaging suite is to integrate therapeutic tools and techniques with MR imaging. From surgical planning through specialized imaging systems with minimally invasive surgical applications, new methods are being developed and implemented. This new field of image-guided therapy will require extensive clinical development and evaluation for applications in the urinary tract. This will require a large concentrated interdisciplinary effort of surgeons, radiologists, computer scientists, engineers, and physicists. Successful integration of basic research and clinical work will result in a number of cutting-edge technologies with direct clinical application in the urinary tract. Initial projects have included biopsies, endoscopies, and real-time procedural control of high-temperature and cryogenic ablations. It is anticipated that the current surge in image-guided interventions will motivate even more research activity in this field, and will ultimately define the role of MR imaging guidance in urologic intervention and surgery.

Percutaneous needle biopsy of localized pulmonary, mediastinal, and pleural diseased tissue with an automatic disposable guillotine soft-tissue needle. Preliminary results

Percutaneous needle biopsy (PNB) of localized thoracic disease has become a widespread procedure in many institutions. The development of special small caliber needles has increased the diagnostic yield of PNB partly by increasing the amount of tissue from biopsy, often enabling histologic examination. Nevertheless, in a significant number of patients only cytopathologic examination is possible on the retrieved biopsy fragments, necessitating the presence of a trained cytopathologist in the biopsy room. Furthermore multiple biopsy needle passages often are required, increasing the risk for complications such as pneumothorax. We have evaluated the use of a small-caliber tissue biopsy cutting needle, consistently yielding sufficient biopsy tissue for histologic examination. In 25 pleural and mediastinal lesions, which could be biopsied without passage through aerated lung, there was a 93% sensitivity (7% false-negative results) for neoplasm and a 100% accuracy for benign disease. There were no complications. In 32 patients with lesions of 1 cm in diameter or more surrounded with aerated lung tissue, adequate histologic examination was feasible on every biopsy specimen after only one needle passage. There was an 87% sensitivity of PNB in neoplastic disease (13% false-negatives). In the patients with benign disease, there was a 100% accuracy. There was a 15.6% risk for pneumothorax. In only one patient (3%), however, was chest drainage necessary. One patient (3%) had mild hemoptysis. We conclude that percutaneous biopsy of localized pulmonary, pleural, and mediastinal lesions with a new small-caliber automatic guillotine cutting needle is safe and efficient, enabling recovery of sufficient tissue for histologic examination with a single-pass procedure, thus minimizing the risk for pneumothorax, eliminating the need for a cytopathologist in the biopsy room, and shortening the duration of the procedure.

Clinical perspective: the importance of imaging in diffuse liver disease and hepatic vascular disorders

The diagnosis of hepatobiliary disorders is based on the patient's history and physical examination and is augmented by laboratory findings, imaging studies, and histology. Radiographic imaging is especially helpful for identifying structural lesions and vascular abnormalities. In cholestatic disease, imaging of the biliary tree is essential to identify extrahepatic biliary obstruction. In hepatocellular diseases, imaging studies narrow the differential diagnosis and guide further testing. In this clinical overview, the role of radiographic imaging in hepatobiliary disorders is reviewed.

Percutaneous abscess drainage: current applications for critically ill patients

Radiologically guided percutaneous abscess drainage (PAD) was first reported in 1977. Since this time, technological advances in imaging, improved catheter technology, and increased experience with the procedure have resulted in a tremendous expansion of the indications for PAD. This procedure currently has applications in nearly every organ system of the body. These changes have also contributed to improved success rates, with concurrent minimization of procedure-related complications. The advantages of PAD include simple, rapid performance; feasibility of bedside intensive care unit (ICU) performance; safety; avoidance of general anesthesia; and well-documented efficacy. This procedure has now become well entrenched in clinical medicine and probably ranks with the development of effective antibiotics as the most significant improvement in the treatment of abscesses in the past century. PAD is ideally suited for the treatment of critically ill ICU patients. We discuss technical developments over the past 15 years; general principles of patient preparation and catheters are also reviewed. Current applications of PAD in each organ system are discussed.

Flow cytometric analysis and cytokeratin typing of human lung tumors. A preliminary study

In the current study a comparative analysis of keratin typing and DNA content was carried out in human lung tumors from transthoracic fine needle aspiration biopsies (TFNAB) (18 patients) or from surgically resected tumor tissues (14 patients). According to the cytologic and histologic features, 2 of the 32 tumors were diagnosed as benign tumors, 11 as squamous cell carcinomas, 12 as adenocarcinomas, and 7 as undifferentiated large cell carcinomas. Two cases in the adenocarcinoma and one in the undifferentiated large cell carcinoma groups were pulmonary metastasis or second primary tumors. Malignant cells of tumors which reacted positively with KK8.60 anticytokeratin polypeptides No. 10 and 11 (and hence contain keratinizing cells) displayed diploid DNA content in a flow cytometric assay regardless of their cytologic or histologic appearance. In contrast, all tumors which lacked such positive cells (most of which were defined as adenocarcinomas and undifferentiated tumors) were hyperdiploid. The close correlation between high DNA content and both malignancy and the absence of advanced squamous differentiation (keratinization) suggests that such combined analysis may provide new tools for the cytologic diagnosis and prognosis of lung cancers.

Metabolic basis for management of the septic surgical patient

The physiologic events accompanying postoperative septic complications in surgical patients represent a coordinated response to bacterial invasion, which is aimed at maintaining the function of key organ systems. When sepsis is prolonged or overwhelming, physiologic dysfunction and multiorgan failure develop. This review outlines the pathophysiologic response to sepsis and correlates it with recent therapeutic advances in the metabolic management of the postoperative septic patient.