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

Evaluation of CT-Guided Ultra-Low-Dose Protocol for Injection Guidance in Preparation of MR-Arthrography of the Shoulder and Hip Joints in Comparison to Conventional and Low-Dose Protocols

To evaluate patients’ radiation exposure undergoing CT-guided joint injection in preparation of MR-arthrography. We developed a novel ultra-low-dose protocol utilizing tin-filtration, performed it in 60 patients and compared the radiation exposure (DLP) and success rate to conventional protocol (26 cases) and low-dose protocol (37 cases). We evaluated 123 patients’ radiation exposure undergoing CT-guided joint injection from 16 January–21 March. A total of 55 patients received CT-guided joint injections with various other examination protocols and were excluded from further investigation. In total, 56 patients received shoulder injection and 67 received hip injection with consecutive MR arthrography. The ultra-low-dose protocol was performed in 60 patients, the low-dose protocol in 37 patients and the conventional protocol in 26 patients. We compared the dose of the interventional scans for each protocol (DLP) and then evaluated success rate with MR-arthrography images as gold standard of intraarticular or extracapsular contrast injection. There were significant differences when comparing the DLP of the ultra-low-dose protocol (DLP 1.1 ± 0.39; p < 0.01) to the low dose protocol (DLP 5.3 ± 3.24; p < 0.01) as well as against the conventional protocol (DLP 22.9 ± 8.66; p < 0.01). The ultra-low-dose protocol exposed the patients to an average effective dose of 0.016 millisievert and resulted in a successful joint injection in all 60 patients. The low dose protocol as well as the conventional protocol were also successful in all patients. The presented ultra-low-dose CT-guided joint injection protocol for the preparation of MR-arthrography demonstrated to reduce patients’ radiation dose in a way that it was less than the equivalent of the natural radiation exposure in Germany over 3 days—and thereby, negligible to the patient.

Body-Mounted Robotic System for MRI-Guided Shoulder Arthrography: Cadaver and Clinical Workflow Studies

This paper presents an intraoperative MRI-guided, patient-mounted robotic system for shoulder arthrography procedures in pediatric patients. The robot is designed to be compact and lightweight and is constructed with nonmagnetic materials for MRI safety. Our goal is to transform the current two-step arthrography procedure (CT/x-ray-guided needle insertion followed by diagnostic MRI) into a streamlined single-step ionizing radiation-free procedure under MRI guidance. The MR-conditional robot was evaluated in a Thiel embalmed cadaver study and healthy volunteer studies. The robot was attached to the shoulder using straps and ten locations in the shoulder joint space were selected as targets. For the first target, contrast agent (saline) was injected to complete the clinical workflow. After each targeting attempt, a confirmation scan was acquired to analyze the needle placement accuracy. During the volunteer studies, a more comfortable and ergonomic shoulder brace was used, and the complete clinical workflow was followed to measure the total procedure time. In the cadaver study, the needle was successfully placed in the shoulder joint space in all the targeting attempts with translational and rotational accuracy of 2.07 ± 1.22 mm and 1.46 ± 1.06 degrees, respectively. The total time for the entire procedure was 94 min and the average time for each targeting attempt was 20 min in the cadaver study, while the average time for the entire workflow for the volunteer studies was 36 min. No image quality degradation due to the presence of the robot was detected. This Thiel-embalmed cadaver study along with the clinical workflow studies on human volunteers demonstrated the feasibility of using an MR-conditional, patient-mounted robotic system for MRI-guided shoulder arthrography procedure. Future work will be focused on moving the technology to clinical practice.

[MR and CT arthrography in cartilage imaging : Indications and implementation]

BACKGROUND

The imaging of chondral pathologies is an essential part in the work-up of acute and chronic joint diseases. Besides conventional MR imaging, CT and MR arthrography are well-established methods in evaluating articular cartilage. The application of these techniques requires knowledge of indications and safe injection procedures by the performing radiologist.

PURPOSE

Our goal is to describe the techniques of cross-sectional arthrographies of different joints, give an overview of general and joint-specific considerations for practical application as well as provide typical indications for cartilage imaging.

MATERIALS AND METHODS

A selective PubMed literature search concerning "arthrography", "CT arthrography", "MR arthrography", "arthrography cartilage", "arthrography wrist", "arthrography elbow", "arthrography shoulder", "arthrography hip", "arthrography knee", "arthrography ankle", "arthrography complications", "arthrography imaging guidance" "osteochondral lesion", "cartilage imaging" and "cartilage lesion" was performed.

RESULTS AND CONCLUSION

CT and MR arthrography are valuable and safe tools in cartilage imaging. They are useful to verify and specify chondral pathologies, usually after conventional MR imaging, and have an important role in evaluating the stability and therefore in therapeutic decision making of osteochondral lesions. CT arthrography is not only a substitute technique in case of MR contraindications, it can be advantageous in small joints (wrist, elbow, ankle) compared to MR arthrography due to its higher image resolution. Fluoroscopic guided joint puncture is still the most commonly used image guidance method, but the role of ultrasound is steadily increasing. Joint traction in MR arthrography is a promising technique to improve cartilage visualization, though it is not yet used in clinical routine imaging.

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.

Freehand direct arthrography of the shoulder using near real-time guidance in an open 1.0-T MRI scanner

OBJECTIVE

To assess the technical success and duration of magnetic resonance imaging (MRI)-guided freehand direct shoulder arthrography (FDSA) with near real-time imaging implemented in a routine shoulder MRI examination on an open 1.0-T MRI scanner, and to assess the learning curve of residents new to this technique.

METHODS

An experienced MRI interventionalist (the expert) performed 125 MRI-guided FDSA procedures, and 75 patients were treated by one of three residents without previous experience in MRI-guided FDSA. Technical success rate and duration of MRI-guided FDSA of the expert and the residents were compared. The residents' learning curves were assessed. The occurrence of extra-articular deposition and leakage of contrast media from the puncture site and the subsequent impairment of image interpretation were retrospectively analyzed.

RESULTS

Overall technical success was 97.5 %. The expert needed overall fewer puncture needle readjustments and was faster at puncture needle positioning (p < 0.01). The learning curve of the residents, however, was steep. They leveled with the performance of the expert after ≈ 15 interventions. With a minimal amount of training all steps of MRI-guided FDSA can be performed in ≤10 min.

CONCLUSION

Magnetic resonance-guided FDSA in an open 1.0-T MRI scanner can be performed with high technical success in a reasonably short amount of time. Only a short learning curve is necessary to achieve expert level.

Epinephrine-enhanced computed tomographic arthrography of the canine shoulder

The aim of this study was to investigate the effect of epinephrine-enhanced computed tomographic arthrography (CTA) on the image sharpness of the lateral and medial glenohumeral ligaments (LGHL and MGHL, respectively), biceps tendon (BT) and joint cartilage (JC) in the canine shoulder. The shoulders of eight normal dogs were examined using a 4-slice helical CT scanner. The right shoulders were injected with Iohexol and the left shoulders with a mixture of Iohexol and epinephrine. CTA images were obtained after 1, 3, 5, 9, 13, 20 and 30 min and the image sharpness of the intra-articular structures in both shoulders was graded for visibility. The attenuation values were measured to examine the persistence of contrast appearance. Admixture of epinephrine and Iohexol significantly improved the image sharpness of the LGHL and the BT, especially on delayed CTA images. The use of epinephrine did not negatively affect post-CTA recovery.

Ultrasound guidance to perform intra-articular injection of gadolinium-based contrast material for magnetic resonance arthrography as an alternative to fluoroscopy: the time is now

Magnetic resonance (MR) imaging has been definitively established as the reference standard in the evaluation of joints in the body. Similarly, magnetic resonance arthrography has emerged as a technique that has been proven to increase significantly the diagnostic performance if compared with conventional MR imaging, especially when dealing with fibrocartilage and articular cartilage abnormalities. Diluted gadolinium can be injected in the joint space using different approaches: under palpation using anatomic landmarks or using an imaging guidance, such as fluoroscopy, computed tomography, or ultrasound. Fluoroscopy has been traditionally used, but the involvement of ionizing radiation should represent a remarkable limitation of this modality. Conversely, ultrasound has emerged as a feasible, cheap, quick, and radiation-free modality that can be used to inject joints, with comparable accuracy of fluoroscopy. In the present paper, we discuss the advantages and disadvantages of using fluoroscopy or ultrasound in injecting gadolinium-based contrast agents in joints to perform magnetic resonance arthrography, also in view of the new EuroSAFE Imaging initiative promoted by the European Society of Radiology and the recent updates to the European Atomic Energy Community 2013/59 directive on the medical use of ionizing radiation.

KEY POINTS

• Intra-articular contrast agent injection can be performed using different imaging modalities • Fluoroscopy is widely used, but uses ionizing radiation • Ultrasound is an accurate, quick, and radiation-free modality for joint injection • X-rays should be avoided when other radiation-free modalities can be used.

Comparison of image quality of shoulder CT arthrography conducted using 120 kVp and 140 kVp protocols

OBJECTIVE

To compare the image quality of shoulder CT arthrography performed using 120 kVp and 140 kVp protocols.

MATERIALS AND METHODS

Fifty-four CT examinations were prospectively included. CT scans were performed on each patient at 120 kVp and 140 kVp; other scanning parameters were kept constant. Image qualities were qualitatively and quantitatively compared with respect to noise, contrast, and diagnostic acceptability. Diagnostic acceptabilities were graded using a one to five scale as follows: 1, suboptimal; 2, below average; 3, acceptable; 4, above average; and 5, superior. Radiation doses were also compared.

RESULTS

Contrast was better at 120 kVp, but noise was greater. No significant differences were observed between the 120 kVp and 140 kVp protocols in terms of diagnostic acceptability, signal-to-noise ratio, or contrast-to-noise ratio. Lowering tube voltage from 140 kVp to 120 kVp reduced the radiation dose by 33%.

CONCLUSION

The use of 120 kVp during shoulder CT arthrography reduces radiation dose versus 140 kVp without significant loss of image quality.

Accuracy of abduction-external rotation MRA versus standard MRA in the diagnosis of intra-articular shoulder pathology

The goal of this study was to compare the accuracy of abduction-external rotation magnetic resonance arthrography (ABERMRA) with standard MRA in the diagnosis of intra-articular shoulder pathology.One hundred three consecutive patients undergoing preoperative direct MRA and subsequent arthroscopic examination were included in the study. Seventy-eight patients underwent standard MRA and 25 underwent ABERMRA. Specialist-trained musculoskeletal radiologists reported all scans, and attending shoulder surgeons performed all arthroscopies. Arthroscopic assessment revealed 11 partial-thickness rotator cuff tears, 3 full-thickness tears, 64 labral lesions (48 soft tissue and 16 significant bony), and 17 superior labrum anterior-posterior (SLAP) tears. The sensitivity/specificity for standard MRA was 0.56/0.99 for partial-thickness rotator cuff tears, 1.00/1.00 for full-thickness rotator cuff tears, 0.75/0.91 for soft tissue labral tears, 0.58/1.00 for significant bony glenoid lesions, and 0.50/0.91 for SLAP tears. Abduction-external rotation magnetic resonance arthrography increased the sensitivity/specificity to 1.00/0.85 for soft tissue labral tears, 0.75/1.00 for significant bony glenoid lesions, and 1.00/1.00 for SLAP tears, although it missed 2 of 2 partial-thickness rotator cuff tears.This study suggests that standard MRA is a valuable investigation tool for instability, SLAP tears, and rotator cuff tears, although limitations exist. Additional ABERMRA sequences appear to improve the diagnostic accuracy of soft tissue anterior and posterior labral tears, SLAP tears, and significant bony glenoid lesions and should be routinely requested by shoulder surgeons when ordering MRAs to obtain the maximum benefit from this invasive investigation.

Glenohumeral joint instability

Due to the configuration of its bony elements, the glenohumeral joint is the most mobile joint of the body, but also an inherently unstable articulation. Stabilization of the joint is linked to a complex balance between static and dynamic soft tissue stabilizers. Because of complex biomechanics, and the existence of numerous classifications and acronyms to describe shoulder instability lesions, this remains a daunting topic for most radiologists. In this article we provide a brief review of the anatomy of the glenohumeral joint, as well as the classifications and the pathogenesis of shoulder instability. Technical aspects related to the available imaging techniques (including computed tomography [CT] arthrography, magnetic resonance imaging [MRI], and MR arthrography) are reviewed. We then describe the imaging findings related to shoulder instability, focusing on those elements that are important to the clinician.

MRI image overlay: Application to arthrography needle insertion

Magnetic Resonance Imaging (MRI) offers great potential for planning, guiding, monitoring and controlling interventions. MR arthrography (MRAr) is the imaging gold standard for assessing small ligament and fibrocartilage injury in joints. In contemporary practice, MRAr consists of two consecutive sessions: (1) an interventional session where a needle is driven to the joint space and MR contrast is injected under fluoroscopy or CT guidance; and (2) a diagnostic MRI imaging session to visualize the distribution of contrast inside the joint space and evaluate the condition of the joint. Our approach to MRAr is to eliminate the separate radiologically guided needle insertion and contrast injection procedure by performing those tasks on conventional high-field closed MRI scanners. We propose a 2D augmented reality image overlay device to guide needle insertion procedures. This approach makes diagnostic high-field magnets available for interventions without a complex and expensive engineering entourage. In preclinical trials, needle insertions have been performed in the joints of porcine and human cadavers using MR image overlay guidance; in all cases, insertions successfully reached the joint space on the first attempt.

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.

CT arthrography, MR arthrography, PET, and scintigraphy in osteoarthritis

CT arthrography and MR arthrography are accurate methods for the study of surface cartilage lesions and cartilage loss. They also provide information on subchondral bone and marrow changes, and ligaments and meniscal lesions that can be associated with osteoarthritis. Nuclear medicine also offers new insights in the assessment of the disease. This article discusses the strengths and limitations of CT arthrography and MR arthrography. It also highlights nuclear medicine methods that may be relevant to the study of osteoarthritis in research and clinical practice.

Radiation exposure from musculoskeletal computerized tomographic scans

BACKGROUND

Computerized tomographic scans are routinely obtained to evaluate a number of musculoskeletal conditions. However, since computerized tomographic scans expose patients to the greatest amounts of radiation of all imaging modalities, the physician must be cognizant of the effective doses of radiation that are administered. This investigation was performed to quantify the effective doses of computerized tomographic scans that are performed for various musculoskeletal applications.

METHODS

The digital imaging archive of a single institution was retrospectively reviewed to identify helical computerized tomographic scans that were completed to visualize the extremities or spine. Imaging parameters were recorded for each examination, and dosimetry calculator software was used to calculate the effective dose values according to a modified protocol derived from publication SR250 of the National Radiological Protection Board of the United Kingdom. Computerized tomographic scans of the chest, abdomen, and pelvis were also collected, and the effective doses were compared with those reported by prior groups in order to validate the results of the current study.

RESULTS

The mean effective doses for computerized tomographic scans of the chest, abdomen, and pelvis (5.27, 4.95, and 4.85 mSv, respectively) were consistent with those of previous investigations. The highest mean effective doses were recorded for studies evaluating the spine (4.36, 17.99, and 19.15 mSv for the cervical, thoracic, and lumbar spines, respectively). In the upper extremity, the effective dose of a computerized tomographic scan of the shoulder (2.06 mSv) was higher than those of the elbow (0.14 mSv) and wrist (0.03 mSv). Similarly, the effective dose of a hip scan (3.09 mSv) was significantly higher than those observed with knee (0.16 mSv) and ankle (0.07 mSv) scans.

CONCLUSIONS

Computerized tomographic scans of the axial and appendicular skeleton are associated with substantially elevated radiation exposures, but the effective dose declines substantially for anatomic structures that are further away from the torso.

Glenohumeral joint injection: a comparative study of ultrasound and fluoroscopically guided techniques before MR arthrography

To assess the variability in accuracy of contrast media introduction, leakage, required time and patient discomfort in four different centres, each using a different image-guided glenohumeral injection technique. Each centre included 25 consecutive patients. The ultrasound-guided anterior (USa) and posterior approach (USp), fluoroscopic-guided anterior (FLa) and posterior (FLp) approach were used. Number of injection attempts, effect of contrast leakage on diagnostic quality, and total room, radiologist and procedure times were measured. Pain was documented with a visual analogue scale (VAS) pain score. Access to the joint was achieved in all patients. A successful first attempt significantly occurred more often with US (94%) than with fluoroscopic guidance (72%). Leakage of contrast medium did not cause interpretative difficulties. With US guidance mean room, procedure and radiologist times were significantly shorter (p < 0.001). The USa approach was rated with the lowest pre- and post-injection VAS scores. The four image-guided injection techniques are successful in injection of contrast material into the glenohumeral joint. US-guided injections and especially the anterior approach are significantly less time consuming, more successful on the first attempt, cause less patient discomfort and obviate the need for radiation and iodine contrast.

Percutaneous radiofrequency ablation of liver dome hepatocellular carcinoma invisible on ultrasonography: a new targeting strategy

Targeting of index tumours is prerequisite to their radiofrequency ablation. However, small hepatocellular carcinomas (HCCs) in the liver dome are often invisible on ultrasonography, thus causing difficulty in their targeting. In cases with multinodular HCCs, adjacent HCC lesions with compact iodized oil retention can be used as anatomic landmarks to guide radiofrequency (RF) ablation of such nodules under fluoroscopy. We present two cases in which nodules that were difficult to target with conventional methods were successfully treated by RF ablation using this targeting strategy.

Cumulative patient effective dose in cardiology

Medical radiation from X-rays and nuclear medicine is the largest non-natural (man-made) source of radiation exposure in Western countries. The aim of this study was to assess the individual cumulative effective dose in patients admitted to our cardiology ward. We collected a cumulative radiological history from a structured questionnaire and access to hospital records in 50 consecutive adult patients (36 males; age, 66.7+/-10.8 years) admitted to the Institute of Clinical Physiology in Pisa. The cumulative effective dose was assessed as an indicator of stochastic risk of cancer. We derived the effective dose for each individual examination from the Medical Imaging Guidelines of the European Commission (2001). On average, each patient underwent a median of 36 examinations (interquartile range, 23-46). The median cumulative effective dose was 60.6 mSv. Three types of procedures were responsible for approximately 86% of the total collective effective dose: (i) arteriography and interventional cardiology (12% of examinations, 48% of average dose per patient); (ii) nuclear medicine (5% of examinations, 21% of average dose per patient); and (iii) CT (4% of examinations, 17% of average dose per patient). The median estimated extra risk of cancer was approximately 1 in 200 exposed subjects. In conclusion, the average contemporary cardiological patient is exposed to a significant cumulative effective dose from diagnostic and therapeutic interventions. It is important to log cumulative dose for each patient at the time of each examination. Every effort should be made to justify the indications and to optimize the doses.

Newly developed application system for CT-guided puncture based on multidetector row CT without CT fluoroscopy

PURPOSE

The aim of this article is to describe a preliminary clinical experience with a new multidetector CT (MDCT) system (GuideShot system) for CT-guided intervention.

MATERIALS AND METHODS

This system enabled simultaneous acquisition and quick display of three axial CT images. Only a single-shot mode was used, with no continuous CT fluoroscopic (CTF) mode. The exposure and the table movement could be controlled by the interventional radiologist using foot pedal switches that are on the floor beside the table. We used this system for biopsy (n = 48), drainage tube placement (n = 7), and hook wire placement prior to video-assisted thoracic surgery (n = 69).

RESULTS

Technical success was achieved in all 124 cases. In 123 of 124 cases, each intervention was done within a single breath-hold (99%). The table controller was used in 22 cases (17.7%), and the central portion of the target or the needle tip was easily shifted into the CT collimation after a single table movement.

CONCLUSION

This new system improved Z-axis orientation for the interventional radiologist and enabled rapid interventional procedures without the CTF system. MDCT with this system could be one of the options when single-slice CT with CTF is replaced by MDCT.

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.

Acromial morphology: effects of suboptimal radiographs

Acromial morphology is one of the important factors related to rotator cuff pathology, especially if there is acromial encroachment onto the supraspinatus tendon. This is the rationale for many surgeons performing an acromioplasty, based on preoperative radiographs, in their treatment of rotator cuff disease. However, geometric measurements of the acromion are dependent on the radiographic view, and suboptimal radiographs of the scapula might bias the acromial morphology on the radiographs. Our objective was to study the effect of suboptimal lateral-view radiographs of the scapula on 6 acromial angles, which have been correlated with rotator cuff pathology, by use of a computational method. Anatomic landmarks were digitized on 12 cadaveric scapulae via a spatial linkage system. A coordinate system based on the scapula was then created that allowed projection of the anatomic landmarks on the sagittal plane and simulated the optimal lateral-view radiograph of the scapula. By rotating the coordinate system in the coronal plane (cranial and caudal projections) and axial plane (anterior and posterior projections) with 5 degrees, 10 degrees, 15 degrees, and 20 degrees increments, 16 suboptimal lateral-view radiographs of the scapula were simulated. Significant differences in the 6 acromial angles (P < .01) between the optimal and suboptimal lateral-view radiographs of the scapula were found in almost every cranial and caudal projection. Rotating the projection in the axial plane did not significantly affect the acromial angles (P > .05) up to 20 degrees of rotation in the anterior and posterior direction. Of the 6 different acromial angles, the acromial slope was least affected when the projection was varied. In contrast, the anterior slope of the acromion was highly affected by errors in the projection.

CT-guided percutaneous biopsy of spinal lesions

Accurate diagnosis of spine lesions is important for its successful management. Imaging–guided percutaneous biopsy is gaining increasing acceptance as a means for obtaining tissue for diagnosis. Most biopsies can be rapidly performed under local anaesthesia, with little patient discomfort and improved safety. Spinal anatomy is, however, complex with many adjacent vital structures. Good knowledge of anatomy and precise needling technique is, therefore, important. Today, biopsy of spinal lesions is best performed under computed tomography (CT) fluoroscopic guidance. Indications for imaging-guided biopsy include confirming metastasis in a patient with a known primary tumour, determining the nature of a solitary bone lesion, excluding malignancy in vertebral body compression, and investigating for infection. Among the various issues to be considered are site of lesion, location of adjacent vital structures, approach, and type and size of needle. Complications are rare, particularly when a meticulous technique is applied. In summary, CT-guided percutaneous biopsy is a safe and an effective technique for the evaluation of spinal lesions and useful in planning therapy.

CT-guided core biopsy of subchondral bone and intervertebral space in suspected spondylodiskitis

OBJECTIVE

Our objective was to determine the diagnostic performance of CT-guided core biopsy including both intervertebral disks and subchondral bone in suspected spondylodiskitis and compare the results with those for other biopsy techniques.

CONCLUSION

CT-guided core biopsy of subchondral bone and intervertebral space compares favorably to previously published studies because histology can provide the diagnosis even when no specific infectious agent is isolated.

CT Fluoroscopy–guided Biopsy of the Lung or Upper Abdomen with a Breath-hold Monitoring and Feedback System: A Prospective Randomized Controlled Clinical Trial

PURPOSE

To prospectively determine the clinical effectiveness of a breath-hold monitoring and feedback system in computed tomographic (CT) fluoroscopy-guided biopsies in which respiratory motion is a problem.

MATERIALS AND METHODS

Institutional review board approval and oral and written informed consent were obtained. This study was HIPAA compliant. A bellows-based system was used to monitor respiration and provide patient feedback. A randomized controlled clinical trial compared intermittent mode CT fluoroscopy-guided biopsies of the lung or upper abdomen performed with (n = 56) and without (n = 57) the bellows system. Inclusion criteria for 113 patients were lesions 6 cm or smaller in maximum dimension that were not affixed to the chest or abdominal wall. Primary outcome measurements were CT fluoroscopy exposure time and patient dose. Wilcoxon rank sum, chi(2), and Fisher exact tests were used for statistical analysis.

RESULTS

Median CT fluoroscopy exposure time was 12.6 seconds (range, 2.4-44.4 seconds) for the bellows group and 18.0 seconds (range, 6.0-118.0 seconds) for the nonbellows group (P = .004). Patient dose was decreased in the bellows group (median dose, 29.5 mGy; range, 4.7-135.8 mGy) versus the nonbellows group (median, 41.3 mGy; range, 11.8-155.9 mGy) (P = .01). Lesions were accessed successfully with one needle puncture attempt in 43 of 56 patients (77%) in the bellows group and 30 of 57 patients (53%) in the nonbellows group (P = .007). Pneumothorax developed in 11 of 50 patients (22%) in the bellows group who underwent lung biopsy compared with 16 of 50 (32%) patients in the nonbellows group.

CONCLUSION

A breath-hold monitoring and feedback system allows depiction of mobile target lesions throughout CT fluoroscopy-guided biopsy of the lung and upper abdomen.