Radiation dosimetry at CT fluoroscopy: physician's hand dose and development of needle holders

Petre E, Marinelli B, Sarkar D, Barral M, H Cornelis F. Percutaneous liver interventions with robotic systems: a systematic review of available clinical solutions

OBJECTIVE

Robotic-guided interventions are emerging techniques that are gradually becoming a common tool for performing biopsies and tumor ablations in liver. This systematic review aims to evaluate their advancements, challenges, and outcomes.

METHODS

A systematic review was conducted using the PubMed database to identify relevant articles published between January 2000 and February 2023. Inclusion criteria focused on studies that assessed robotic systems for percutaneous liver biopsies and tumor ablations. Data extraction was performed to collect information on study characteristics; robotic systems; components and software; imaging modality; degree of freedom; and needle insertion methods. The outcome measures analyzed were procedure time, radiation dose, and accuracy.

RESULTS

10 studies met the inclusion criteria. The robotic devices used included MAXIO, EPIONE, ROBIO-EX, AcuBot, and ACE robotic systems. The data set consisted of 429 percutaneous thermal ablations and 57 biopsies, both robot-guided. On average, the mean deviation of probes was reduced by 30% (from 1.6 vs 3.3 mm to 2.4 vs 3.9 mm (p < 0.001)), and 40% (p < 0.05) fewer readjustments were required during the robotic-assisted interventions. Moreover, robotic systems contributed to a reduction in operating time, ranging from 15% (18.3 vs 21.7 min, p < 0.001) to 25% (63.5 vs 87.4 min, p < 0.001). Finally, the radiation dose delivered to both the patient and the operator was decreased by an average of 50% (p < 0.05) compared to manual procedures.

ADVANCES IN KNOWLEDGE

Robotic systems could provide precise navigation and guidance during liver biopsies and percutaneous ablations.

Role of interventional radiology in upper abdominal cancer pain management

Background

The major indication for celiac plexus block is abdominal pain that is nonresponsive to analgesic interventions; often these patients are nonresponsive to high-dose opioid therapies. One of the most common indications for the celiac plexus block is the treatment of abdominal pain associated with pancreatic cancer.

Aim of the work

The differences between two techniques (ultrasound and fluoroscopy guided) are highlighted in terms of effectiveness by means of a Visual Analog Scale (VAS), a percentage reduction in daily morphine consumption and any complications are recorded and evaluated at the time of implementation of each technique from start to finish.

Results

Through the data that have been recorded and statistically analyzed, we found that the mean values of VAS were decreased in the two groups, and there was statistically significant difference between ultrasound and fluoroscopy groups.

Conclusions

It is noticeable and good in conducting this research that there are no major complications that include a large space on the study sample, despite the presence of some minor with no significant differences between ultrasound and fluoroscopy groups. This effective celiac block, regardless of the technique used, produced immediate analgesics that permitted significant opioid decrease in the study sample with a significant improvement in the unwanted adverse effects on account of opioids.

Radiation Exposure and Protection in Computed Tomography Fluoroscopy

Computed tomography (CT) fluoroscopy-guided procedures, such as those used for percutaneous biopsy, drainage, and radiofrequency ablation, are highly safe and quite often very successful due to the precision offered by the real-time, high-resolution tomographic images. Even so, international guidelines raised concerns regarding operator exposure to high doses of radiation during these procedures. In light of these concerns, operators conducting CT fluoroscopy-guided procedures not only need to be cognizant of the exposure risk but also exhibit sufficient knowledge of radiation protection. This paper reviews the current literature on experimental and clinical studies of radiation exposure doses to operators during CT fluoroscopy-guided procedures. In addition to the literature review, this paper also introduces different approaches that can be implemented to ensure appropriate radiation protection.

Radiation dose and image quality of CT fluoroscopy with partial exposure mode

PURPOSE

The present study aimed to evaluate the scan technique of computed tomography (CT)-guided puncture procedures using partial exposure mode (PEM) on the radiation dose of the operator's hand and image quality.

METHODS

Radiation dose was evaluated using three types of scanning methods: one-shot scan (OS), OS with a bismuth shield added (OSBismuth), and a half-scan (i.e., PEM) capable of an adjustable exposure angle. Dose evaluation was performed using a torso phantom, while a circular phantom simulating the liver parenchyma and lesions was used for image quality evaluation. For each scanning method, four measurements were made to determine the radiation dose to the operator's hand and the dose distribution on the surface of the patient's torso; the output-dose profile was determined from five measurements. Image quality was evaluated in terms of contrast and contrast-to-noise ratio (CNR). Analysis of variance (ANOVA) or Friedman test were used for comparison between groups as appropriate. The post hoc tests were Tukey's honestly difference (HSD) test for parametric data or Wilcoxon signed rank test with Bonferroni correction for nonparametric data.

RESULTS

The PEM yielded a radiation dose to the operator's hand that was 84% (0.35 vs. 2.33 mGy) lower than that of the OS. The dose to the patient's torso was reduced by 35% and 68% for the OSBismuth and PEM, respectively, relative to that of the OS. Compared with the CNR of the other two scanning methods (OS, 2.9±0.1; OSBismuth, 2.9±0.1), the PEM increased the standard deviation and decreased the CNR (2.1±0.04, Tukey's HSD, P < 0.001 for all). Images acquired with PEM showed visibility equivalent to that of other scanning methods when window conditions were adjusted.

CONCLUSION

This study demonstrated that CT-guided puncture procedure using PEM effectively reduces the operator's exposure to radiation while minimizing image quality deterioration.

First experience of efficacy and radiation exposure in 320-detector row CT fluoroscopy-guided interventions

OBJECTIVE

We investigated the efficacy and exposure to radiation in 320-detector row computed tomography fluoroscopy-guided (CTF-guided) interventions.

METHODS

We analysed 231 320-detector row CTF-guided interventions (207 patients over 2 years and 6 months) in terms of technical success rates, clinical success rates, complications, scanner settings, overall radiation doses (dose-length product, mGy*cm), patient doses of peri-interventional CT series, and interventional CT (including CTF), as a retrospective cohort study. The relationships between patient radiation dose and interventional factors were assessed using multivariate analysis.

RESULTS

Overall technical success rate was 98.7% (228/231). The technical success rates of biopsies, drainages, and aspirations were 98.7% (154/156), 98.5% (66/67), and 100% (8/8), respectively. The clinical success rate of biopsies was 93.5% (146/156). All three major complications occurred in chest biopsies. The median total radiation dose was 522.4 (393.4-819.8) mGy*cm. Of the total radiation dose, 87% was applied during the pre- and post-interventional CT series. Post-interventional CT accounted for 24.4% of the total radiation dose. Only 11.4% of the dose was applied by CTF-guided intervention. Multilinear regression demonstrated that male sex, body mass index, drainage, intervention time, and helical scan as post-interventional CT were significantly associated with higher dose.

CONCLUSION

The 320-detector row CTF interventions achieved a high success rate. Dose reduction in post-interventional CT provides patient dose reduction without decreasing the technical success rates.

ADVANCES IN KNOWLEDGE

This is the first study on the relationship between various interventional outcomes and patient exposure to radiation in 320-detector row CTF-guided interventions, suggesting a new perspective on dose reduction.

Occupational radiation dose to the lens of the eye of medical staff who assist in diagnostic CT scans

PURPOSE

We investigated occupational dose to the lens of the eye for CT-assisting personnel for diagnostic purposes using a radio-photoluminescent glass dosimeter (RPLD) and evaluate compliance with the new equivalent dose limit for the lens of the eye (20 mSv/year). Further, we proposed the implementation of "multiple protective measures" and estimated its effect.

METHOD

An eye lens dosimeter clip was developed specifically to attach RPLDs inside radiation safety glasses in an L-shape. Using a total of six RPLDs attached to the radiation safety glasses, the 3-mm dose-equivalent (Hp(3)) to the lens of the eye for medical staff (n = 11; 6 intensive care physicians, 2 pediatricians, 3 radiological technologists) who assisted patients during CT scan for "diagnostic" purpose (n = 91) was measured. We evaluated the dose reduction efficiencies with radiation safety glasses and bag-valve-mask extension tube. We also estimated the protection efficiency with radiation protection curtain introduced in front of the staff's face via the phantom experiment.

RESULTS

Without wearing radiation safety glasses, Hp(3) to the lens of the eye was greatest for intensive care physicians (0.49 mSv/procedure; allowing 40 procedures to be performed annually), followed by pediatricians (0.30 mSv/procedure; 66 procedures annually) and radiological technologists (0.28 mSv/procedure; 71 procedures annually). Use of each type of protective tools: radiation safety glasses (0.07-mm-Pb), bag-valve-mask extension tube (20 cm) and radiation protective curtain (0.25-mm-Pb), reduced Hp(3) to the lens of the eye by 51%, 31% and 61%, respectively.

CONCLUSION

Intensive care physicians perform most assisted ventilations with the bag-valve-mask during "diagnostic" CT scans, and may exceed the equivalent dose limit for the lens of the eye if radiation safety glasses are not worn. If "multiple protective measures" are implemented, compliance with the equivalent dose limit for the lens of the eye should be achievable without placing significant burdens on physicians or medical institutions.

THE EFFICACY OF RADPAD AS A RADIATION PROTECTION TOOL IN CT FLUOROSCOPY GUIDED LUNG BIOPSIES

Computed tomography fluoroscopy is now the preferred technique for percutaneous lung biopsies. However, concern regarding operator and patient radiation dose remains, which warrants further exploration into dose optimisation tools. This phantom-study aims to assess the dose reduction capabilities of RADPAD, a single-use patient drape designed to decrease staff exposure to scattered radiation. Dosemeters at the waist and eye levels were used to determine the whole-body and lens exposure during simulated lung biopsy procedures while using RADPAD and other combinations of personal protective equipment. RADPAD resulted in a 36% and 38% dose reduction for whole-body and eye exposure, respectively. However, when used in combination with radioprotective eyewear and aprons, RADPAD did not reduce the radiation dose further. Consequently, the use of standard personal protective equipment is a more cost-effective option for staff dose reduction. RADPAD is useful in the reduction of radiation dose to unprotected regions.

Dose to the interventional radiologist in CTF-guided procedures

The aim of this work was to assess the occupational dose received by an interventional radiologist (IR) during computed tomography fluoroscopy (CTF)-guided procedures; to identify the most exposed areas of the body including the hands and fingers; to suggest recommendations for individual monitoring; and to improve radiation safety of the practice. A total of 53 CTF-guided procedures were studied. Twelve whole-body dosimeters were worn by the IR in each procedure for the assessment of the personal dose equivalent, H_p(10), on the chest, waist, and back, both over and under the lead apron, as well as the personal dose equivalent, H_p(0.07), on both arms, knees, and feet. Special gloves with casings to fit extremity dosimeters were prepared to assess H_p(0.07) to the fingers. The measured chest dose values were higher than those on the waist and back; the dominant hand or the left side was the most exposed. In general, the ring, middle, and index fingers of the dominant hand were the most exposed (maximum in the 36-39 mSv range), while wrist dose was negligible compared to finger doses. Based on the results obtained the following recommendations are suggested: protective devices (lead aprons, thyroid shield, and goggles) should be worn; H_p(10) should be assessed at the chest level both above and below the lead apron; finger doses can be measured on the basis of each middle finger; the arm closer to the beam should be monitored; and finally, a wrist dosimeter will not provide useful information.

The use of needle holders in CTF guided biopsies as a dose reduction tool

PURPOSE

The purpose of this study was to evaluate the efficacy of needle holders in reducing staff hand exposure during biopsies guided by computed tomography fluoroscopy (CTF), through the analysis of data acquired during a detailed monitoring study, undertaken in parallel with an ongoing optimization process to reduce hand irradiation.

METHODS

Hand monitoring was performed with 11 extremity detectors, two per finger (base and tip) and one on the back of the wrist, for the left (dominant) hand, during two series of biopsies with comparable characteristics. The first series (47 biopsies) were performed with only quick-check method (QC) and occasional side-handle (SH) manipulation of the needle. The second series (63 biopsies) were performed after introducing needle holders (NH) in the course of an optimization process.

RESULTS

Choice of technique (QC, QC + NH, QC + SH) by the interventional radiologist (IR) was related to biopsy difficulty. Measured hand exposure was low (< 1 mSv) for all QC-only procedures, and for most of the QC + NH procedures. Occasional side-handle manipulation still occurred during challenging biopsies, so that 8% of biopsies in the second series accounted for ~70% of total fingertip dose (~90 mSv). The methodology used allowed a detailed insight into the dose reduction achievable with needle holders during real procedures, without the limitations of phantom measurements.

CONCLUSIONS

Needle holders proved effective in reducing mean hand exposure during clinical procedures where real-time manipulation was necessary. Occasional side-handle manipulation was found to contribute disproportionately to hand exposure. This highlights the importance of individual hand monitoring during CTF guided procedures.

A Review of Radiation Protection Requirements and Dose Estimation for Staff and Patients in CT Fluoroscopy

The combination of fluoroscopically guided interventional procedures with computed tomography (CTF) has become widespread around the world. The benefits of CTF include the ability to obtain a real-time visualization of the entire body, increased target accuracy and improved visualization of biopsy needles. Modern CTF units work with variable frame rates for image selection, and therefore the dose distributions for patients and staff can considerably vary, creating growing concern in terms of the occupational exposure of interventionists and the drawback of a higher exposure of the patient. A literature review of the latest CTF publications is summarized in this article. A wide range of CTF studies reveal different treatment methods used in clinical practice, and therefore the differences in the exposures between them; as well as in the radiation protection tools and dose monitoring. Further optimization of radiation protection methods, harmonization of exposure patterns as well as training and education of CTF staff on the basis of the information in the survey, are strongly recommended.

Improvement of image quality and dose management in CT fluoroscopy by iterative 3D image reconstruction

OBJECTIVES

The objective of this study was to assess the influence of an iterative CT reconstruction algorithm (IA), newly available for CT-fluoroscopy (CTF), on image noise, readers' confidence and effective dose compared to filtered back projection (FBP).

METHODS

Data from 165 patients (FBP/IA = 82/74) with CTF in the thorax, abdomen and pelvis were included. Noise was analysed in a large-diameter vessel. The impact of reconstruction and variables (e.g. X-ray tube current I) influencing noise and effective dose were analysed by ANOVA and a pairwise t-test with Bonferroni-Holm correction. Noise and readers' confidence were evaluated by three readers.

RESULTS

Noise was significantly influenced by reconstruction, I, body region and circumference (all p ≤ 0.0002). IA reduced the noise significantly compared to FBP (p = 0.02). The effect varied for body regions and circumferences (p ≤ 0.001). The effective dose was influenced by the reconstruction, body region, interventional procedure and I (all p ≤ 0.02). The inter-rater reliability for noise and readers' confidence was good (W ≥ 0.75, p < 0.0001). Noise and readers' confidence were significantly better in AIDR-3D compared to FBP (p ≤ 0.03). Generally, IA yielded a significant reduction of the median effective dose.

CONCLUSION

The CTF reconstruction by IA showed a significant reduction in noise and effective dose while readers' confidence increased.

KEY POINTS

• CTF is performed for image guidance in interventional radiology. • Patient exposure was estimated from DLP documented by the CT. • Iterative CT reconstruction is appropriate to reduce image noise in CTF. • Using iterative CT reconstruction, the effective dose was significantly reduced in abdominal interventions.

Evaluation of a Robotic Assistance-System For Percutaneous Computed Tomography-Guided (CT-Guided) Facet Joint Injection: A Phantom Study

Background

The aim of this study was to compare robotic assisted and freehand facet joint puncture on a phantom model in regards to time requirements and puncture accuracy.

Material/Methods

Forty facet joints were punctured, 20 using a robotic guidance system and 20 using a freehand procedure. Side and height of the facet joints were randomized and identical for both groups. Procedural accuracy, defined as axial and sagittal deviation, as well as the number of corrections were assessed. Procedure times for each step were documented and time requirements for pre-positioning, reconstruction, planning, and total intervention were calculated.

Results

Total procedure time for robotic guidance was 259±111 seconds versus 119±77 seconds for freehand procedure (p=1.0). Procedural accuracy for robotic guidance was significantly higher with 0 corrections versus 1.3 corrections for freehand procedure (p=0.02). Needle deviation in the robotics arm was 0.35±1.1 mm in the axial and 2.15±1.2 mm in the sagittal reconstruction.

Conclusions

Robotic assisted puncture of the facet joint allowed accurate positioning of the needle with a lower number of needle readjustments. Higher procedural accuracy was marginally offset by a slightly longer intervention time.

Radiation Exposure of Interventional Radiologists During Computed Tomography Fluoroscopy-Guided Renal Cryoablation and Lung Radiofrequency Ablation: Direct Measurement in a Clinical Setting

INTRODUCTION

Computed tomography (CT) fluoroscopy-guided renal cryoablation and lung radiofrequency ablation (RFA) have received increasing attention as promising cancer therapies. Although radiation exposure of interventional radiologists during these procedures is an important concern, data on operator exposure are lacking.

MATERIALS AND METHODS

Radiation dose to interventional radiologists during CT fluoroscopy-guided renal cryoablation (n = 20) and lung RFA (n = 20) was measured prospectively in a clinical setting. Effective dose to the operator was calculated from the 1-cm dose equivalent measured on the neck outside the lead apron, and on the left chest inside the lead apron, using electronic dosimeters. Equivalent dose to the operator's finger skin was measured using thermoluminescent dosimeter rings.

RESULTS

The mean (median) effective dose to the operator per procedure was 6.05 (4.52) μSv during renal cryoablation and 0.74 (0.55) μSv during lung RFA. The mean (median) equivalent dose to the operator's finger skin per procedure was 2.1 (2.1) mSv during renal cryoablation, and 0.3 (0.3) mSv during lung RFA.

CONCLUSION

Radiation dose to interventional radiologists during renal cryoablation and lung RFA were at an acceptable level, and in line with recommended dose limits for occupational radiation exposure.

Gafchromic XR-QA2 film as a complementary dosimeter for hand-monitoring in CTF-guided biopsies

Computed tomography fluoroscopy (CTF) is a useful imaging technique to guide biopsies, particularly lung biopsies, but it also has the potential for very high hand exposures, despite use of quick-check method and needle holders whenever feasible. Therefore, reliable monitoring is crucial to ensure the safe use of CTF. This is a challenge, because ring dosimeters monitor exposure only at the base of one finger, while the fingertips may be exposed to the highly collimated CT beam. In this work we have explored the possibility of using Gafchromic XR-QA2 self-developing film as a complementary dosimeter to quantify hand exposure during CTF-guided biopsies. A glove used in a previous study and designed to contain 11 TLDs was adapted to include Gafchromic strips 7 mm wide, covering the fingers. A total of 22 biopsies were successfully performed wearing this GafTLD glove under sterile gloves, and the IR reported no difficulty or reduction of dexterity while wearing it. Comparison of dose distributions obtained from digitization of the Gafchromic film strips and absolute Hp(0.07) readings from TLDs showed good agreement, despite some positional uncertainty due to relative movement. Per procedure, doses at the base of the ring finger can be as low as 3%-8% of hand dose maximum. Accumulated dose at the base of the ring finger was four times lower than the dose maximum.

Robot-assisted microwave thermoablation of liver tumors: a single-center experience

PURPOSE

To evaluate and compare the needle placement accuracy, patient dose, procedural time, complication rate and ablation success of microwave thermoablation using a novel robotic guidance approach and a manual approach.

METHODS

We performed a retrospective single-center evaluation of 64 microwave thermoablations of liver tumors in 46 patients (10 female, 36 male, mean age 66 years) between June 2014 and February 2015. Thirty ablations were carried out with manual guidance, while 34 ablations were performed using robotic guidance. A 6-week follow-up (ultrasound, computed tomography and MRI) was performed on all patients.

RESULTS

The total procedure time and dose-length product were significantly reduced under robotic guidance (18.3 vs. 21.7 min, [Formula: see text]; 2216 vs. 2881 mGy[Formula: see text]cm, [Formula: see text]). The position of the percutaneous needle was more accurate using robotic guidance (needle deviation 1.6 vs. 3.3 mm, [Formula: see text]). There was no significant difference between both groups regarding the complication rate and the ablation success.

CONCLUSION

Robotic assistance for liver tumor ablation reduces patient dose and allows for fast positioning of the microwave applicator with high accuracy. The complication rate and ablation success of percutaneous microwave thermoablation of malignant liver tumors using either CT fluoroscopy or robotic guidance for needle positioning showed no significant differences in the 6-week follow-up.

Evaluation of an X-Ray Dose Profile Derived from an Optically Stimulated Luminescent Dosimeter during Computed Tomographic Fluoroscopy

The purpose of this study was to evaluate scatter radiation dose to the subject surface during X-ray computed tomography (CT) fluoroscopy using the integrated dose ratio (IDR) of an X-ray dose profile derived from an optically stimulated luminescent (OSL) dosimeter. We aimed to obtain quantitative evidence supporting the radiation protection methods used during previous CT fluoroscopy. A multislice CT scanner was used to perform this study. OSL dosimeters were placed on the top and the lateral side of the chest phantom so that the longitudinal direction of dosimeters was parallel to the orthogonal axis-to-slice plane for measurement of dose profiles in CT fluoroscopy. Measurement of fluoroscopic conditions was performed at 120 kVp and 80 kVp. Scatter radiation dose was evaluated by calculating the integrated dose determined by OSL dosimetry. The overall percent difference of the integrated doses between OSL dosimeters and ionization chamber was 5.92%. The ratio of the integrated dose of a 100-mm length area to its tails (−50 to −6 mm, 50 to 6 mm) was the lowest on the lateral side at 80 kVp and the highest on the top at 120 kVp. The IDRs for different measurement positions were larger at 120 kVp than at 80 kVp. Similarly, the IDRs for the tube voltage between the primary X-ray beam and scatter radiation was larger on the lateral side than on the top of the phantom. IDR evaluation suggested that the scatter radiation dose has a high dependence on the position and a low dependence on tube voltage relative to the primary X-ray beam for constant dose rate fluoroscopic conditions. These results provided quantitative evidence supporting the radiation protection methods used during CT fluoroscopy in previous studies.

Comparison of CT Fluoroscopy-Guided Manual and CT-Guided Robotic Positioning System for In Vivo Needle Placements in Swine Liver

PURPOSE

To compare CT fluoroscopy-guided manual and CT-guided robotic positioning system (RPS)-assisted needle placement by experienced IR physicians to targets in swine liver.

MATERIALS AND METHODS

Manual and RPS-assisted needle placement was performed by six experienced IR physicians to four 5 mm fiducial seeds placed in swine liver (n = 6). Placement performance was assessed for placement accuracy, procedure time, number of confirmatory scans, needle manipulations, and procedure radiation dose. Intra-modality difference in performance for each physician was assessed using paired t test. Inter-physician performance variation for each modality was analyzed using Kruskal-Wallis test.

RESULTS

Paired comparison of manual and RPS-assisted placements to a target by the same physician indicated accuracy outcomes was not statistically different (manual: 4.53 mm; RPS: 4.66 mm; p = 0.41), but manual placement resulted in higher total radiation dose (manual: 1075.77 mGy/cm; RPS: 636.4 mGy/cm; p = 0.03), required more confirmation scans (manual: 6.6; RPS: 1.6; p < 0.0001) and needle manipulations (manual: 4.6; RPS: 0.4; p < 0.0001). Procedure time for RPS was longer than manual placement (manual: 6.12 min; RPS: 9.7 min; p = 0.0003). Comparison of inter-physician performance during manual placement indicated significant differences in the time taken to complete placements (p = 0.008) and number of repositions (p = 0.04) but not in other study measures (p > 0.05). Comparison of inter-physician performance during RPS-assisted placement suggested statistically significant differences in procedure time (p = 0.02) and not in other study measures (p > 0.05).

CONCLUSIONS

CT-guided RPS-assisted needle placement reduced radiation dose, number of confirmatory scans, and needle manipulations when compared to manual needle placement by experienced IR physicians, with equivalent accuracy.

Image-guided microwave thermoablation of hepatic tumours using novel robotic guidance: an early experience

OBJECTIVE

To evaluate and compare novel robotic guidance and manual approaches based on procedural accuracy, procedural time, procedural performance, image quality as well as patient dose during image-guided microwave thermoablation.

METHOD

The study was prospectively performed between June 2013 and December 2013 using 70 patients. Forty randomly selected patients (group 1) were treated with manual guidance and 30 patients (group 2) were treated using a novel robotic guidance. Parameters evaluated were procedural accuracy, total procedural time, procedural performance, quantitative/qualitative image quality and patient dose. Two-sided Student's t test and Wilcoxon rank-sum test were used to test the significance of the data and p values less than 0.05 were considered statistically significant.

RESULT

Accuracy parameters were significantly higher in group 2 (all p < 0.05). Total procedural time showed a mean time difference of 3 min (group 2 > group 1; p = 0.0008). Volume CT dose index and dose-length product were significantly lower for group 2 compared to group 1 (all p < 0.05) for CT fluoroscopy imaging. Total procedural performance score was higher for group 2 compared to group 1 (p = 0.0001). Image quality parameters were insignificant between examined groups.

CONCLUSION

The novel robotic guided approach improved the accuracy of targeting the target tumour, reduced patient dose and increased procedural performance (which influences the procedural safety) during ablation.

KEY POINTS

• Few reports are available in the literature regarding robotic-assisted liver microwave ablation. • The robotic guided approach improved accuracy of localizing the target tumour. • Radiation dose on patients was reduced with the robotic guidance. • Numbers of insertions and readjustments were reduced, lowering chances of complications.

Safety and efficacy of a new procedure for treating traumatic iliopsoas hematoma: a retroperitoneoscopic approach

BACKGROUND

Surgical treatment is often recommended for traumatic iliopsoas hematoma. Open surgeries lead to severe surgical trauma, and minimally invasive surgeries cannot completely remove the hematoma. A new treatment protocol for traumatic iliopsoas hematoma by retroperitoneoscopic approach has been introduced. The goal of this study was to determine the safety and efficacy of retroperitoneoscopic approach used to remove iliopsoas hematoma.

METHODS

Between January 2009 and July 2012, 13 patients were diagnosed of traumatic iliopsoas hematoma. Retroperitoneoscopic surgeries were performed on all patients to remove the hematomas after admission. The size of hematoma, VASA score and neurologic status were dynamic evaluated before and after surgery. Soft tissue damage and complications caused by retroperitoneoscopic approach also were recorded and evaluated.

RESULTS

We performed retroperitoneoscopic surgery to remove traumatic iliopsoas hematoma successfully on 13 patients without complications. The mean procedure time was 52.5 ± 13.4 min, and mean blood loss was 30.7 ± 9.2 ml. Hematoma was completely removed confirmed by ultrasound after surgery. Pain in the affected lower abdominal and thigh immediately was relieved totally for ten patients and partly for three patients after surgery. Quadriceps strength was restored to grade 5 and pain completely disappeared 2 months postoperatively on all patients. Numbness along the femoral nerve distribution disappeared for 11 patients and improved for 2 patients until the last follow-up. None of 13 patients suffered from infection or a new hematoma during follow-up.

CONCLUSIONS

Retroperitoneoscopic approach is a safe and effective procedure alternative to conventional surgical approach for treating traumatic iliopsoas hematoma in terms of complete removal of hematoma, minimal invasiveness, absence of radiation, and rapid recovery.

Radiation exposure in CT-guided interventions

PURPOSE

To investigate radiation exposure in computed tomography (CT)-guided interventions, to establish reference levels for exposure, and to discuss strategies for dose reduction.

MATERIALS AND METHODS

We analyzed 1576 consecutive CT-guided procedures in 1284 patients performed over 4.5 years, including drainage placements; biopsies of different organs; radiofrequency and microwave ablations (RFA/MWA) of liver, bone, and lung tumors; pain blockages, and vertebroplasties. Data were analyzed with respect to scanner settings, overall radiation doses, and individual doses of planning CT series, CT intervention, and control CT series.

RESULTS

Eighty-five percent of the total radiation dose was applied during the pre- and post-interventional CT series, leaving only 15% applied by the CT-guided intervention itself. Single slice acquisition was associated with lower doses than continuous CT-fluoroscopy (37 mGy cm vs. 153 mGy cm, p<0.001). The third quartile of radiation doses varied considerably for different interventions. The highest doses were observed in complex interventions like RFA/MWA of the liver, followed by vertebroplasty and RFA/MWA of the lung.

CONCLUSIONS

This paper suggests preliminary reference levels for various intervention types and discusses strategies for dose reduction. A multicenter registry of radiation exposure including a broader spectrum of scanners and intervention types is needed to develop definitive reference levels.

Percutaneous transthoracic needle biopsy of small (≤ 1 cm) lung nodules under C-arm cone-beam CT virtual navigation guidance

OBJECTIVES

To describe our initial experience with percutaneous transthoracic needle biopsy (PCNB) of small (≤1 cm) lung nodules using a cone-beam computed tomography (CBCT) virtual navigation guidance system in 105 consecutive patients.

METHODS

One hundred and five consecutive patients (55 male, 50 female; mean age, 62 years) with 107 small (≤1 cm) lung nodules (mean size, 0.85 cm ± 0.14) underwent PCNBs under CBCT virtual-navigation guidance system and constituted our study population. Procedural details-including radiation dose, sensitivity, specificity, diagnostic accuracy and complication rates of CBCT virtual navigation guided PCNBs-were described.

RESULTS

The mean number of pleural passages with the coaxial needle, biopsies, CT acquisitions, total procedure time, coaxial introducer dwelling time, and estimated radiation exposure during PCNBs were 1.03 ± 0.21, 3.1 ± 0.7, 3.4 ± 1.3, 10.5 min ± 3.2 and 7.2 min ± 2.5, and 5.72 mSv ± 4.19, respectively. Sixty nodules (56.1 %) were diagnosed as malignant, 38 (35.5 %) as benign and nine (8.4 %) as indeterminate. The sensitivity, specificity, and diagnostic accuracy of CBCT virtual-navigation-guided PCNB for small (≤1 cm) nodules were 96.7 % (58/60), 100 % (38/38) and 98.0 % (96/98), respectively. Complications occurred in 13 (12.1 %) cases; pneumothorax in seven (6.5 %) and haemoptysis in six (5.6 %).

CONCLUSION

CBCT virtual-navigation-guided PCNB is a highly accurate and safe diagnostic method for small (≤1 cm) nodules.

CT-fluoroscopy in chest interventional radiology: sliding scale of imaging parameters based on radiation exposure dose and factors increasing radiation exposure dose

AIM

To verify the usefulness of a sliding scale of imaging parameters to reduce radiation exposure during chest interventional radiology (IR), and to identify factors that increase radiation exposure in order to obtain acceptable computed tomography (CT)-fluoroscopy image quality.

MATERIALS AND METHODS

The institutional review board approved this retrospective study, for which the need for informed consent was waived. Interventional radiologists determined the optimal CT-fluoroscopy imaging parameters using the sliding scale based on the radiation exposure dose. The imaging parameters were changed from those generating low radiation (120 kV/10 mA, 1.2 mGy/s) to others generating higher radiation exposure until acceptable image quality was obtained for each procedure. Validation of the imaging parameter sliding scale was done using regression analysis. Factors that increase radiation exposure were identified using multiple regression analysis.

RESULTS

In 125 patients, 217 procedures were performed, of which 72 procedures (33.2%, 72/217) were performed with imaging parameters of minimum radiation exposure, but increased radiation exposure was necessary in 145 (66.8%, 145/217). Significant correlation was found between the radiation exposure dose and the percentage achievement of acceptable image quality (R(2) = 0.98). Multivariate regression analysis showed that high body weight (p < 0.0001), long device passage (p < 0.0001), and lesions above the aortic arch (p = 0.04) were significant independent factors increasing radiation exposure.

CONCLUSION

Although increased radiation exposure dose might be necessary to obtain acceptable chest CT-fluoroscopy images depending on the patient, lesion, and procedure characteristics, a sliding scale of imaging parameters helps to reduce radiation exposure.

Initial experience of percutaneous transthoracic needle biopsy of lung nodules using C-arm cone-beam CT systems

OBJECTIVE

To describe our initial experience with percutaneous transthoracic biopsy (PCNB) of lung nodules using C-arm cone-beam CT (CBCT).

MATERIALS

Seventy-one consecutive patients with lung nodules of 30 mm or smaller underwent CBCT-guided PCNB using a coaxial cutting needle. We evaluated the procedure time, coaxial introducer dwell time, the numbers of pleural passages, coaxial introducer repositionings and CT acquisitions, as well as the technical success rate and radiation doses. Diagnostic accuracy, sensitivity, specificity and incidence of complications were also evaluated.

RESULTS

PCNB was performed for 71 nodules: 63 solid, 6 part-solid and 2 ground-glass nodules. The procedure time, coaxial introducer dwell time, numbers of pleural passages, coaxial introducer repositionings and CT acquisitions were 17.9+/-5.9 min, 8.7+/-3.8 min, 1.1+/-0.4, 0.2+/-0.5 and 2.9+/-0.7, respectively. The technical success rate was 100% and the radiation dose was 272+/-116 mGy. Thirty-six nodules (50.7%) were diagnosed as malignant, 25 (35.2%) as benign and 10 (14.1%) as indeterminate. Diagnostic accuracy, sensitivity, specificity and incidence of complications were 98.4%, 97%, 100% and 38%, respectively. Complications included pneumothorax in 18 patients (25.4%), haemoptysis in 10 (14.1%) and chest pain in one (1.4%).

CONCLUSION

Under CBCT guidance, PCNB of lung nodules can be performed accurately, providing both real-time fluoroscopic guidance and CT imaging capabilities.

CT fluoroscopy-guided lung biopsy versus conventional CT-guided lung biopsy: a prospective controlled study to assess radiation doses and diagnostic performance

OBJECTIVE

We evaluated radiation doses, complication rates, and diagnostic accuracy for CT-guided percutaneous needle aspiration biopsy (NAB) procedures of pulmonary lesions performed with or without fluoroscopic guidance.

METHODS

A total of 142 patients were prospectively enrolled to receive CT-guided NAB with (Group I, n = 72) or without (Group II, n = 70) fluoroscopic guidance. Outcome measurements were patient and doctor radiation dose, and complication rate. Sensitivity, specificity and accuracy were calculated based on 123 NAB results.

RESULTS

The mean estimated effective patient radiation dose was 6.53 mSv in Group I and 2.72 mSv in Group II (p < 0.001). The mean estimated effective doctor dose was 0.054 mSv in Group I and 0.029 mSv in Group II (p < 0.001). The complication rate was significantly different between the two groups (13.4% versus 31.4%, p = 0.012). Sensitivity, specificity and accuracy for diagnosing pulmonary lesions were 97.8%, 100% and 98.4% in group I and 95.3%, 100% and 89.5% in group II (p > 0.05).

CONCLUSIONS

CT fluoroscopy-guided NAB of pulmonary lesions provides high diagnostic accuracy and can be performed with significantly fewer complications. However, radiation exposure to both patient and doctor were significantly higher than conventional CT-guided NAB.

Radiation dose reduction in computed tomography: techniques and future perspective

Despite universal consensus that computed tomography (CT) overwhelmingly benefits patients when used for appropriate indications, concerns have been raised regarding the potential risk of cancer induction from CT due to the exponentially increased use of CT in medicine. Keeping radiation dose as low as reasonably achievable, consistent with the diagnostic task, remains the most important strategy for decreasing this potential risk. This article summarizes the general technical strategies that are commonly used for radiation dose management in CT. Dose-management strategies for pediatric CT, cardiac CT, dual-energy CT, CT perfusion and interventional CT are specifically discussed, and future perspectives on CT dose reduction are presented.

A review of radiology staff doses and dose monitoring requirements

Studies of radiation doses received during X-ray procedures by radiology, cardiology and other clinical staff have been reviewed. Data for effective dose (E), and doses to the eyes, thyroid, hands and legs have been analysed. These data have been supplemented with local measurements to determine the most exposed part of the hand for monitoring purposes. There are ranges of 60-100 in doses to individual tissues reported in the literature for similar procedures at different centres. While ranges in the doses per unit dose-area product (DAP) are between 10 and 25, large variations in dose result from differences in the sensitivity of the X-ray equipment, the type of procedure and the operator technique, but protection factors are important in maintaining dose levels as low as possible. The influence of shielding devices is significant for determining the dose to the eyes and thyroid, and the position of the operator, which depends on the procedure, is the most significant factor determining doses to the hands. A second body dosemeter worn at the level of the collar is recommended for operators with high workloads for use in assessment of effective dose and the dose to the eye. It is proposed that the third quartile values from the distributions of dose per unit DAP identified in the review might be employed in predicting the orders of magnitude of doses to the eye, thyroid and hands, based on interventional operator workloads. Such dose estimates could be employed in risk assessments when reviewing protection and monitoring requirements. A dosemeter worn on the little finger of the hand nearest to the X-ray tube is recommended for monitoring the hand.

Clinical feasibility and usefulness of CT fluoroscopy-guided percutaneous transhepatic biliary drainage in emergency patients with acute obstructive cholangitis

OBJECTIVE

To evaluate the feasibility of CT fluoroscopy (CTF)-guided percutaneous transhepatic biliary drainage (PTBD) in emergency patients with acute obstructive cholangitis.

MATERIALS AND METHODS

The study included 28 patients admitted to the emergency center due to obstructive jaundice and found to require urgent biliary drainage, as well as judged to have a suitable peripheral bile duct for a CTF-guided puncture (at least 4 mm in width). Prior to the CTF-guided puncture, a CT scan was performed to evaluate bile duct dilatation and the underlying causes of biliary obstruction. If the patient was judged to be a suitable candidate, a CTF-guided PTBD was performed in the same CT unit without additional fluoroscopic guidance. Technical feasibility of the procedure was investigated with the evaluation of overall success rate and causes of failure.

RESULTS

A hepatic puncture was attempted at the left lobe in 23 patients and right lobe in five patients. The procedure was successful in 24 of 28 patients (86%) Successful biliary puncture was achieved on the first attempt in 16 patients, the second attempt in five patients, and the third attempt in three patients. The causes of failure included guide wire twisting in one patient, biliary puncture failure in two patients, and poor visualization of the guide wire in one patient. There were no significant procedure-related complication.

CONCLUSION

The CTF-guided PTBD is technically feasible and highly successful in patients judged to have a suitable indication. Moreover, although the procedure is unfamiliar and inconvenient to interventionalists, it has economical advantages in that it saves time and manpower. We believe this method can be used in the emergency patients requiring urgent biliary drainage as an alternative for the fluoroscopy-guided PTBD.

Percutaneous drainage of psoas abscess under real-time computed tomography fluoroscopic guidance

OBJECTIVES

The goal of our study was to determine the usefulness of percutaneous abscess drainage under guidance of computed tomography (CT) fluoroscopy.

MATERIALS AND METHODS

Our subjects were 21 patients (seven women, 14 men; mean age 64 years; age range 30-87 years) who had undergone percutaneous drainage of 26 psoas abscess lesions under CT fluoroscopic guidance between May 2001 and January 2008. Drainage methods involved a needle puncture, insertion of a guidewire, serial dilations, and the exchange of the needle with a drainage tube. The procedures were guided by use of a helical CT scanner that provided real-time fluoroscopic reconstruction.

RESULTS

Percutaneous drainage under real-time CT fluoroscopic guidance was successfully performed in every procedure. Use of real-time CT fluoroscopy allowed rapid assessment of needle, guidewire, and catheter placement. No patient had serious complications related to the drainage procedure. The mean procedure time required to drain one lesion was 35.6 +/- 13.6 min. Mean period after the drainage procedure until complete disappearance of the abscess as confirmed by CT was 12.4 +/- 10.0 days (range 3-46 days).

CONCLUSION

CT fluoroscopy is useful in achieving accurate and safe drainage of abnormal psoas fluid collections.

Musculoskeletal biopsies using computed tomography fluoroscopy

OBJECTIVE

To determine the diagnostic yield, accuracy, and safety of computed tomography (CT) fluoroscopy guidance for musculoskeletal biopsies.

MATERIALS AND METHODS

A retrospective analysis of musculoskeletal biopsies performed with CT fluoroscopy guidance over a 2-year period was made. Data collected were biopsy sites, CT fluoroscopic times, and biopsy results. Results were categorized as the following: positive, negative (but diagnostic), or nondiagnostic. Reference standard consisted of 5 years of follow-up to verify results.

RESULTS

Ninety-five CT fluoroscopy-guided musculoskeletal biopsies were performed. Bone biopsies comprised 83% (79/95), and soft tissue biopsies comprised 17% (16/95). The mean age was 54 years (range, 16-90 years); 40.0% (38/95) were male subjects, and 60.0% (57/95) were female subjects. For all subjects, CT fluoroscopic times ranged from 2 to 310 seconds, with a mean time of 63 seconds and a median time of 34 seconds. The diagnostic yield was 96% (91/95), with a nondiagnostic result in 4% (4/95) of subjects. Diagnostic biopsy specimens showed a positive result in 63% (60/95) of subjects and a negative but diagnostic result in 33% (31/95) of subjects. There were no major complications.

CONCLUSIONS

Computed tomography fluoroscopic-guided musculoskeletal biopsies show a high diagnostic yield and are accurate and safe. The biopsy results are similar or superior to other published reports using conventional CT guidance with only a small overall fraction being nondiagnostic. The benefits of real-time imaging are at the cost of operator exposure to ionizing radiation and the risk of potentially high exposures to both patient and operator. The impact on indications for which lesions are most amenable to percutaneous biopsy using CT fluoroscopy and procedure time has yet to be determined.

Dose reduction during CT fluoroscopy: phantom study of angular beam modulation

PURPOSE

To prospectively evaluate, in a phantom, the dose reductions achievable by using angular beam modulation (ABM) during computed tomographic (CT) fluoroscopy-guided thoracic interventions.

MATERIALS AND METHODS

To enable measurement of organ doses and effective patient dose, a female Alderson-Rando phantom was equipped with thermoluminescent dosimeters (TLDs) in 41 positions, with three TLDs in each position. Additionally, the local dose was assessed in 22 locations above the phantom to estimate the radiation exposure to the radiologist's hand and the patient's skin dose during thoracic interventions. Radiation exposure was performed with a 64-section multidetector CT scanner in the CT fluoroscopy mode, simulating a CT fluoroscopy-guided chest intervention. Effective dose, breast dose, and the dose to the radiologist's hand during the simulated chest intervention were measured with and without ABM. Image noise as an indicator for image quality was compared for both settings. Statistical significance of the measured dose reductions and the image noise was tested by using the paired-samples t test, with P < .05 indicating a significant difference.

RESULTS

ABM significantly reduced the effective patient dose by 35%, the skin dose by 75%, the breast dose by 47% (P < .001 for all), and the physician's hand dose by between 27% (scattered radiation, P = .007) and 72% (direct radiation, P < .001). No significant difference was found in a comparison of the image noise with and that without ABM.

CONCLUSION

ABM leads to significant dose reductions for both patients and personnel during CT fluoroscopy-guided thoracic interventions, without impairing image quality.

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.

CT fluoroscopy: novel application for the treatment of ventricular pathologies

INTRODUCTION

Recent advances in multidetector CT imaging (MDCT) provide real-time "fluoroscopic-like" capabilities with excellent spatial resolution. MDCT fluoroscopy expands our ability to perform image-guided interventions in anatomically complex locations. Although MDCT fluoroscopy is currently used at our institution for a variety of procedures ranging from spinal nerve blocks to RFA ablation, we believe these same techniques can be used to navigate within the ventricles of the central nervous system to treat conditions requiring placement of intraventricular catheters, depth electrodes, or potentially stents for the relief of CSF outlet obstruction.

METHODS

Using three fresh, unfrozen human cadavers, we studied the feasibility of using MDCT fluoroscopy for intraventricular catheter placement and to stent the aqueduct of Sylvius.

RESULTS

The ventricles were entered via a single needle pass and catheters were placed over the wire. Contrast agent was then injected to visualize the distribution. To stent the aqueduct of Sylvius, a wire was passed into the 4th ventricle and a coronary stent was then inserted over the wire and deployed.

CONCLUSION

Based on our success with these procedures, we believe this technique can be used to limit complications and improve efficacy of a number of neurosurgical procedures.

Respiratory motion compensation with tracked internal and external sensors during CT-guided procedures

This paper investigates the possibility of using the motion of a patient's anterior surface in combination with a motion model to compensate for internal respiratory motion during tracked biopsies. Position data from two electromagnetically tracked sensors, one placed on the patient's sternum, the other incorporated into a biopsy needle, were acquired during a liver biopsy. The data were used to evaluate the correlation between the position measurements of the two sensors and to derive an affine motion model to assess respiratory motion compensation for image-guided interventional procedures. The correlation reached up to 94% for ranges of steady respiration. The residual motion of the internal sensor after compensation is reduced by a factor of approximately four.

Respiratory motion compensation with tracked internal and external sensors during CT-guided procedures

This paper investigates the possibility of using the motion of a patient's anterior surface in combination with a motion model to compensate for internal respiratory motion during tracked biopsies. Position data from two electromagnetically tracked sensors, one placed on the patient's sternum, the other incorporated into a biopsy needle, were acquired during a liver biopsy. The data were used to evaluate the correlation between the position measurements of the two sensors and to derive an affine motion model to assess respiratory motion compensation for image-guided interventional procedures. The correlation reached up to 94% for ranges of steady respiration. The residual motion of the internal sensor after compensation is reduced by a factor of approximately four.

Radiation dose to the radiologist's hand during continuous CT fluoroscopy-guided interventions

Computed tomography fluoroscopy (CT fluoroscopy) enables real-time image control over the entire body with high geometric accuracy and, for the most part, without significant interfering artifacts, resulting in increased target accuracy, reduced intervention times, and improved biopsy specimens [1--4]. Depending on the procedure being used, higher radiation doses than in conventional CT-supported interventions might occur. Because the radiologist is present in the CT room during the intervention, he is exposed to additional radiation, which is an important aspect. Initial experience with CT fluoroscopically guided interventions is from the work of Katada et al. in 1994 [5] and only relatively few reports on radiation aspects in CT fluoroscopy are found in the literature [1, 2, 6--11]. To date, there are no reported injuries to patients and radiologists occurring with CT fluoroscopy. The time interval since the wide use of CT fluoroscopy is too short to have data on late effects to the operator using CT fluoroscopy on a daily basis. In addition, the spectrum of CT fluoroscopically guided interventional procedures will expand and more sophisticated procedures requiring longer fluoroscopy times will be performed. Thus, effective exposure reduction is very important. The purpose of our study was to assess the radiation dose to the operator's hand by using data from phantom measurements. In addition, we investigated the effect of a lead drape on the phantom surface adjacent to the scanning plane, the use of thin radiation protective gloves, and the use of different needle holders.

MRI-guided percutaneous cryoablation of renal tumors: use of external manual displacement of adjacent bowel loops

PURPOSE

We sought to investigate retrospectively the safety and effectiveness of using external hand compression to displace adjacent bowel loops during MRI-guided percutaneous cryoablation of renal tumors.

MATERIALS AND METHODS

Fourteen patients (six women, eight men; mean age: 72 years) with 15 renal tumors (mean diameter: 2.4 cm; range: 1.4-4.6 cm) adjacent to bowel were treated with MRI-guided percutaneous cryoablation during which bowel was displaced manually. Bowel loop of concern was ascending colon (n=5), descending colon (n=8), descending colon and small bowel (n=1), ascending colon and small bowel (n=1). To analyze effectiveness of the maneuver, mean distance between tumor margin and bowel before and after the maneuver were compared and analyzed using paired Student's t-test. Minimum distance between iceball edge and adjacent bowel with external manual displacement during freezing was also measured. Safety was assessed by analyzing post-procedural MR imaging for adjacent bowel wall thickening and focal fluid collections as well as patients' clinical and imaging follow-up.

RESULTS

Mean distance between tumor margin and closest adjacent bowel increased from 0.8 cm (range: 0-2 cm) before external manual compression to 2.6 cm (range: 1.6-4.1 cm) with manual displacement (p<0.01). Mean minimum distance between iceball edge and closest adjacent bowel during the procedures was 1.6 cm (range: 0.5-3.5 cm). No evidence of bowel injury was encountered. Twelve of 15 tumors had follow-up (mean: 10 months) that showed no tumor recurrence.

CONCLUSION

MRI-guided percutaneous cryoablation of renal tumors adjacent to bowel can be done safely and effectively using external hand compression to displace bowel loops.

Accuracy and complications in computed tomography fluoroscopy-guided needle biopsies of lung masses

The aim of this study was to determine the diagnostic accuracy and frequency of complications of lung biopsy procedures with or without CTF guidance of needle insertion. Records and images of 99 consecutive percutaneous coaxial cutting needle lung biopsy procedures performed on 85 patients were reviewed retrospectively. Fifty-seven and 42 procedures had been done with and without CTF guidance, respectively. Histological results were compared to diagnosis after surgery or after a follow-up period of 12 months. Diagnostic accuracy and the occurrence of pneumothorax and/or bleeding related to the procedures were registered. The level of accuracy of the diagnosis was comparable. The diagnostic accuracy was 96% (50/52) and 95% (34/36) sensitivity 95% (35/37) and 93% (26/28), specificity 100% (15/15) and 100% (8/8) with CTF and conventional CT techniques, respectively. There were fewer post procedure pneumothoraces using the CTF than conventional technique [26% (15/57) vs. 38% (16/42)], but the difference was not statistically significant (P = 0.274). The insertion of a chest tube was required in only one (2%) procedure using the CTF technique, while this was needed in four (10%) using the conventional technique. Small or large hemorrhages occurred in 23% of the procedures, with no apparent difference between the two groups. In conclusion, CTF-guided biopsy of lung lesions provides high diagnostic accuracy, comparable to that of conventional CT-guided procedures, with a low rate of complications, even for small tumors.

Transthoracic CT-guided biopsy with multiplanar reconstruction image improves diagnostic accuracy of solitary pulmonary nodules

OBJECTIVE

To evaluate the utility of multiplanar reconstruction (MPR) image for CT-guided biopsy and determine factors of influencing diagnostic accuracy and the pneumothorax rate.

MATERIALS AND METHODS

390 patients with 396 pulmonary nodules underwent transthoracic CT-guided aspiration biopsy (TNAB) and transthoracic CT-guided cutting needle core biopsy (TCNB) as follows: 250 solitary pulmonary nodules (SPNs) underwent conventional CT-guided biopsy (conventional method), 81 underwent CT-fluoroscopic biopsy (CT-fluoroscopic method) and 65 underwent conventional CT-guided biopsy in combination with MPR image (MPR method). Success rate, overall diagnostic accuracy, pneumothorax rate and total procedure time were compared in each method. Factors affecting diagnostic accuracy and pneumothorax rate of CT-guided biopsy were statistically evaluated.

RESULTS

Success rates (TNAB: 100.0%, TCNB: 100.0%) and overall diagnostic accuracies (TNAB: 96.9%, TCNB: 97.0%) of MPR were significantly higher than those using the conventional method (TNAB: 87.6 and 82.4%, TCNB: 86.3 and 81.3%) (P < 0.05). Diagnostic accuracy were influenced by biopsy method, lesion size, and needle path length (P < 0.05). Pneumothorax rate was influenced by pathological diagnostic method, lesion size, number of punctures and FEV1.0% (P < 0.05).

CONCLUSION

The use of MPR for CT-guided lung biopsy is useful for improving diagnostic accuracy with no significant increase in pneumothorax rate or total procedure time.

[CT fluoroscopy]

Percutaneous biopsy of pulmonary nodules requires precise needle placement, with the goal of attaining a secure position of the needle for therapeutic or diagnostic purposes as quickly as possible and with minimal tissue damage along the access route. The requirements from the image guidance system during the intervention are, in addition to universal applicability, a quick reaction time and a user-friendly interface. CT fluoroscopy fulfils these requirements, although radiation protection for the patient and radiologist becomes an important issue.