Adjunctive use of C-arm CT may eliminate technical failure in adrenal vein sampling

PURPOSE: To examine whether the use of C-arm computed tomography (CT) during adrenal vein sampling improves the technical success rate of the procedure. MATERIALS AND METHODS: Nine consecutive patients with suspected primary hyperaldosteronism underwent standard adrenal vein sampling that included cortisol stimulation. The procedure was augmented with multiplanar C-arm CT images reconstructed from data acquired during a 180 degrees C-arm rotation. Whenever C-arm CT images showed the sampling catheter to be in the wrong position, the catheter was repositioned. Cortisol response was correlated to C-arm CT findings. RESULTS: All patients had successful and diagnostic adrenal vein sampling. C-arm CT showed sampling catheter malposition in two patients (22%). Repeat C-arm CT after repositioning showed proper catheter location. Cortisol stimulation results and C-arm CT findings were concordant in 100% of cases. CONCLUSIONS: C-arm CT is reliable in confirming the location of sampling catheters during adrenal vein sampling. If the 100% concordance between cortisol stimulation and C-arm CT findings is found in larger groups, the technical success rate may approach 100%. Cortisol stimulation may become obsolete and repeat procedures unnecessary, with significant time and cost savings.     

CT-guided extrapleural drainage of bronchogenic cyst

A patient with a subcarinal bronchogenic cyst is described. The cyst was aspirated using an extrapleural percutaneous approach under CT guidance, employing repeated injections of 4-5 ml of saline to split the parietal pleura from the chest wall. Thus we describe a technique that allows the insertion of a catheter into a cyst and complete evacuation of its contents.     

Percutaneous Transhepatic Drainage of Inaccessible Abdominal Abscesses Following Abdominal Surgery Under Real-Time CT-Fluoroscopic Guidance

This study evaluated the safety, feasibility, and clinical utility of transhepatic drainage of inaccessible abdominal abscesses retrospectively under real-time computed tomographic (CT) guidance. For abdominal abscesses, 12 consecutive patients received percutaneous transhepatic drainage. Abscesses were considered inaccessible using the usual access route because they were surrounded by the liver and other organs. The maximum diameters of abscesses were 4.6–9.5 cm (mean, 6.7 ± 1.4 cm). An 8-Fr catheter was advanced into the abscess cavity through the liver parenchyma using real-time CT fluoroscopic guidance. Safety, feasibility, procedure time, and clinical utility were evaluated. Drainage catheters were placed with no complications in abscess cavities through the liver parenchyma in all patients. The mean procedure time was 18.8 ± 9.2 min (range, 12–41 min). All abscesses were drained. They shrank immediately after catheter placement. In conclusions, this transhepatic approach under real-time CT fluoroscopic guidance is a safe, feasible, and useful technique for use of drainage of inaccessible abdominal abscesses.     

Thin-section multidetector CT angiography of renal artery stents

OBJECTIVE: This study was undertaken as a pilot investigation to compare multidetector CT angiography with conventional catheter angiography for the visualization of the renal artery lumen after renal artery stent placement. SUBJECTS AND METHODS: CT angiography was performed within 24-48 hr of renal artery stent placement in 15 patients. Two patients had bilateral stents, resulting in a total of 17 stents. CT angiography was performed using a multidetector scanner and a bolus of IV contrast material with the scanning delay determined by a small-volume timing bolus. A volumetric data set was acquired through the stented arteries in the axial plane using a 4.0 x 1.25 mm detector configuration and a pitch of 3:1. The stent lumen diameter, as measured on direct CT angiography and curved multiplanar reformations in both the axial and coronal planes, was compared with that measured on catheter angiography. RESULTS: The lumina of all 17 stents were well visualized and patent on both CT angiography and catheter angiography. Anatomic definition, including stent position and wall apposition in the renal artery, correlated well with catheter angiography. The diameter of the renal artery stent lumen measured on catheter angiography (mean, 5.9 +/- 1.3 mm) was greater than that on CT angiography (mean stent lumen diameter for direct axial plane was 4.6 +/- 1.0 mm, for curved multiplanar reformations in the axial plane was 4.3 +/- 1.0 mm, and for curved multiplanar reformations in the coronal plane was 4.4 +/- 1.0 mm) in 14 (82%) of 17 stents. CONCLUSION: CT angiography produced interpretable multiplanar images of the renal artery, even with a metallic stent in place, and was adequate for determining stent patency. Compared with catheter angiography, the intrastent luminal diameter was underestimated in most patients who underwent CT angiography.     

Percutaneous translumbar inferior vena cava cannulation under computed tomography guidance

Percutaneous translumbar inferior vena cava (IVC) cannulation is an alternative approach for central venous catheterization, but there have been sporadic reports of puncture-related complications. To avoid complications during IVC puncture, percutaneous translumbar IVC cannulation was performed under computed tomography (CT) guidance in addition to fluoroscopy in two patients. To perform chemotherapy for recurrent breast cancer, we planned subcutaneous port catheter placement for central venous access. Under CT guidance, the direction and insertion distance of a long elastor needle were adjusted, and the IVC was punctured at the level of the third lumbar vertebra while taking care to avoid the right urinary tract. A guidewire was inserted through the long elastor needle, and a catheter was placed over the guidewire. It was possible to perform central venous catheterization by percutaneous translumbar inferior vena cava cannulation under CT guidance.     

Comprehensive approach to CT-guided procedures with a hand-held guidance device

A technically successful biopsy or drainage procedure performed with computed tomographic (CT) guidance depends on two essential elements: determination of the correct entry point on the patient and placement of the biopsy needle or trocar drainage catheter along a predetermined track. A hand-held guidance device was used in conjunction with the lighting system on the CT scanner and measurements obtained from CT images to achieve this goal in 40 patients. The approach minimized trauma to the patient and decreased the time required for CT.     

Translumbar inferior vena cava catheters for long-term venous access

Forty-six silicone rubber catheters were placed in the inferior vena cava (IVC) of 40 patients via a translumbar approach. No patient suffered retroperitoneal bleeding as determined by means of clinical observation (n = 46), computed tomography (CT) (n = 31), or autopsy (n = 5). Twenty-four catheters were removed after a mean of 51 (range, 2-137) days. No bleeding occurred after catheter removal, as determined by means of clinical observation (n = 24), CT (n = 13), or autopsy (n = 2). Nineteen catheters remained in place after a mean of 65 (range, 13-236) days. Thrombosis-related catheter dysfunction occurred in eight patients, two of whom developed IVC occlusion. Thrombolytic therapy restored catheter function and dissolved clots in all patients. Ten catheter malpositions resulted in venous access failure. Five of these catheters were replaced, four were repositioned, and one spontaneously resumed the original position. It is concluded that percutaneous placement of silicone rubber catheters in the IVC is a satisfactory alternative when catheter placement in the subclavian vein is not feasible.     

Safety considerations in the power injection of contrast media via central venous catheters during computed tomographic examinations.

RATIONALE AND OBJECTIVES. This study addresses the theoretical, experimental, and clinical application of using a central venous catheter system (CVS) for the rapid injection of contrast media during computed tomography (CT). METHODS. Application of Poiseuille's law and the Reynolds equation yielded theoretical data. In-line pressures were measured in experimental models and patients undergoing CT. Diatrizoate meglumine and iohexal contrast media were evaluated. RESULTS. The Reynolds number was consistent with laminar flow, allowing the application of Poiseuille's law. The calculated and experimental catheter tubing-chamber connection pressures were safe for both contrast media, at rates of 1 mL/second for long catheter tubing and 2 mL/second for short tubing. Thirteen patients had measured pressures within safety limits with no complications. CONCLUSIONS. This study establishes that power injection of contrast media via a CVS during CT is a safe procedure. Benefits include no need for peripheral intravenous catheter placement, decreased paramedical staff radiation exposure, and improved CT image quality.     

CT in the management of periappendiceal abscess

Abdominal CT was the primary diagnostic method used to evaluate 40 patients with suspected periappendiceal abscess. Its subsequent impact on patient management was then analyzed for several categories of clinical presentation, including patients with and without a palpable right-lower-quadrant mass and postoperative patients. CT was reliable in distinguishing periappendiceal abscesses from phlegmons; 17 of 18 patients with phlegmons responded promptly to antibiotic therapy alone without need for surgery. Patients with larger, poorly localized abscesses underwent early surgical drainage. CT was successful in guiding percutaneous catheter drainage (nine patients) or aspiration (one patient) of well-localized periappendiceal abscesses in 10 of 11 patients. One attempted catheter drainage guided by sonography was technically unsuccessful. In patients without a palpable right-lower-quadrant mass, CT was helpful in establishing the diagnosis of periappendiceal inflammation. However, there were three false-positive diagnoses in patients with pericecal fluid collections including a ruptured cecal lymphoma, a ruptured cecal diverticulum, and a ruptured corpus luteum cyst. A diagnostic approach with CT is presented in patients with suspected periappendiceal abscess.     

Laser-Assisted Transgraft Embolization: A Technique for the Treatment of Type II Endoleaks

A transgraft embolization (TGE) technique was performed in a patient to treat a type II endoleak. Using a transfemoral arterial approach, the endograft was punctured using a coronary laser catheter aimed toward the type II endoleak nidus, which was treated with Onyx (Medtronic, Minneapolis, Minnesota). TGE resulted in successful embolization, as demonstrated on 1-year follow-up CT angiography, which showed complete elimination of the type II endoleak and shrinkage of the aneurysmal sac. TGE is an alternative to transarterial embolization, translumbar embolization, and transcaval embolization.     

Evaluation of an MR-only interstitial gynecologic brachytherapy workflow using MR-line marker for catheter reconstruction

PurposeMagnetic resonance imaging (MRI) offers excellent soft-tissue contrast enabling the contouring of targets and organs at risk (OARs) during gynecological interstitial brachytherapy procedure. Despite its benefit, one of the main challenges toward MRI-only workflows is that the implanted catheters are not reliably visualized on MR images. This study aims to evaluate the feasibility of MR-only workflow using an in-house MR line marker during interstitial gynecological high-dose-rate (HDR) brachytherapy.Methods and MaterialsTen patients diagnosed with locally advanced cervical cancer treated with HDR brachytherapy were included in this study. The hybrid CT/MR-treated plan was used as the study reference plan. Five users manually reconstructed the catheter's path on MR images (3D T1- and T2-weighted). Subsequently, the dwell positions from the users’ plans were superimposed on the reference plans to evaluate the dosimetric impact of the using MR-only for catheter reconstruction in comparison with hybrid CT/MR approach. Variability of dwell positions between users and reconstruction time was also evaluated.ResultsMore than 96.90% of catheter reconstruction variations were < 2 mm. No statistical differences were reported between MR-only and hybrid CT/MR in gross tumor volume D₉₈ and high-risk clinical target volume D₉₀, respectively. For the OARs (bladder, sigmoid, rectum, and bowel), no significant changes were observed in any dose metrics between MR-only and hybrid CT/MR. The average reconstruction time was 51 ± 10 minutes across all ten patients.ConclusionThe feasibility of MR-only workflow using MR line marker during interstitial gynecological HDR brachytherapy has been validated in this study. The results show that the MR-only workflow is equivalent to the conventional hybrid CT/MR approach in terms of gross tumor volume and high-risk clinical target volume coverage and respecting of OARs dose limits.     

Development of a New Coaxial Balloon Catheter System for Balloon-Occluded Retrograde Transvenous Obliteration (B-RTO)

Purpose To develop a new coaxial balloon catheter system and evaluate its clinical feasibility for balloon-occluded retrograde transvenous obliteration (B-RTO). Methods A coaxial balloon catheter system was constructed with 9 Fr guiding balloon catheter and 5 Fr balloon catheter. A 5 Fr catheter has a high flexibility and can be coaxially inserted into the guiding catheter in advance. The catheter balloons are made of natural rubber and can be inflated to 2 cm (guiding) and 1 cm (5 Fr) maximum diameter. Between July 2003 and April 2005, 8 consecutive patients (6 men, 2 women; age range 33–72 years, mean age 55.5 years) underwent B-RTO using the balloon catheter system. Five percent ethanolamine oleate iopamidol (EOI) was used as sclerosing agent. The procedures, including maneuverability of the catheter, amount of injected sclerosing agent, necessity for coil embolization of collateral draining veins, and initial clinical results, were evaluated retrospectively. The occlusion rate was assessed by postcontrast CT within 2 weeks after B-RTO. Results The balloon catheter could be advanced into the proximal potion of the gastrorenal shunt beyond the collateral draining vein in all cases. The amount of injected EOI ranged from 3 to 34 ml. Coil embolization of the collateral draining vein was required in 2 cases. Complete obliteration of gastric varices on initial follow-up CT was obtained in 7 cases. The remaining case required re-treatment that resulted in complete obstruction of the varices after the second B-RTO. No procedure-related complications were observed. Conclusion B-RTO using the new coaxial balloon catheter is feasible. Gastric varices can be treated more simply by using this catheter system.     

Percutaneous abdominal and pelvic interventional procedures using CT fluoroscopy guidance.

OBJECTIVE: The purpose of our study was to assess the use of low-milliamperage CT fluoroscopy guidance for percutaneous abdominopelvic biopsy and therapeutic procedures. MATERIALS AND METHODS: We reviewed the clinical records and relevant imaging studies of 97 patients who underwent 119 percutaneous CT fluoroscopy-guided abdominal or pelvic procedures: fluid collection aspiration or drainage catheter insertion (n = 59), biopsy (n = 49), hepatocellular carcinoma ethanol ablation (n = 6), chemoneurolysis (n = 4), and brachytherapy catheter insertion (n = 1). These procedures were guided using a helical CT scanner providing real-time fluoroscopy reconstruction at six frames per second. A control panel and video monitor beside the gantry allowed direct operator control during all interventional procedures. RESULTS: One hundred twelve (94.1%) procedures were successfully performed using either a stand-off needle holder and continuous real-time CT fluoroscopy guidance or incremental manual insertion and intermittent CT fluoroscopy to confirm position. Image quality using low milliamperage was adequate for needle or drainage tube placement in all but two low-contrast liver lesions. Two hematomas were accessed but yielded no fluid on aspiration; one drainage procedure was abandoned after the patient developed endotoxic shock. Imaging of ethanol distribution during injection facilitated tumor ablation and neurolytic procedures. CT fluoroscopy allowed rapid assessment of needle, guidewire, dilator, and catheter placement, especially in nonaxial planes. Average CT fluoroscopy time for biopsy and therapeutic procedures was 133 sec (range, 35-336 sec) and 186 sec (range, 20-660 sec), respectively. CONCLUSION: CT fluoroscopy is a practical clinical tool that facilitates effective performance of percutaneous abdominal and pelvic interventional procedures.     

Interventional approach to pancreatic fluid collections

Interventional radiologic catheter drainage may be an effective therapeutic approach to fluid collections complicating acute pancreatitis. Pancreatic pseudocysts and abscess are the most common conditions requiring radiologic intervention. Imaging guidance is best performed under CT control allowing precise definition of access route, catheter placement, and response. Access routes are chosen to avoid traversing vital intervening structures, especially the pleural space, colon, and small bowel. Optimal results are achieved with the use of large-bore multihole catheters, prolonged duration of drainage, and careful collaboration with the surgical team.     

CT引导下经皮胆囊造瘘术治疗高龄、危重急性胆囊炎患者

目的 评估CT引导下经皮胆囊造瘘术治疗高龄、危重急性胆囊炎患者的临床价值并对并发症等问题进行探讨。方法 对16例不能进行急诊胆囊切除手术的高龄、危重急性胆囊炎患者行CT引导下经皮经肝穿刺胆囊造瘘术，在胆囊内置放直径为7～8．5F猪尾引流管引流潴留胆汁，观察胆囊造瘘前后患者临床症状、体征及血白细胞计数的变化情况。结果 16例患者CT引导下经皮胆囊造瘘均获得成功。15例术后12～48h临床症状、体征缓解；1例术后无缓解。5例非结石性胆囊炎术后21～28d拔管后康复；10例结石性胆囊炎30～60d行胆囊切除手术。无严重并发症。结论 CT引导下经皮胆囊造瘘术是1种操作简便、安全有效的胆囊造瘘方法，对于治疗高龄、危重的急性胆囊炎患者具有较为重要的临床价值。     

Pericardial effusion and pericardial compartments after open heart surgery. An analysis by computed tomography and echocardiography

Thirty-three patients with pericardial effusion after open heart surgery were investigated with computed tomography (CT). Twelve of the 33 patients also underwent echocardiography prior to pericardiocentesis. The effusions were typed according to the results of the CT investigation. Because of postoperative adhesions, typical patterns of localized pericardial effusions were found in 16 patients. The localized compartments were seen on the right and left side of the heart and around the aorta and the pulmonary artery. CT was therefore shown to be of value for selecting the approach for drainage with catheter pericardiocentesis.     

Computational flow dynamics in abdominal aortic aneurysm using multislice computed tomography

Following the introduction of a new multislice computed tomography (MSCT) scanner, it has become possible to produce high-speed CT angiography (CTA), the preferred method for imaging in emergent abdominal vascular conditions. Unlike catheter angiography, multislice CTA not only depicts the vessels but also allows perfusion in adjacent organs to be assessed. To make the most effective diagnostic use of multi-detector row CTA and three-dimensional image post-processing, radiologists must be familiar with the optimal CTA protocols and the typical CT findings in various emergent vascular conditions using computational flow dynamics (CFD). This article describes a technical approach to estimating the blood flow state of human abdominal aortic aneurysms (AAA) in more detail by constructing realistic three-dimensional (3D) vessel models using CFD methods, focusing on pre- and postoperative cases.     

Central line pump infusion and large volume mediastinal contrast extravasation in CT

The use of multidetector CT scanners for CT angiography requires rapid injection of radiographic contrast media. Central venous catheters are now widely used for this purpose. Several complications may occur while using central venous access for rapid, large volume contrast injection such as catheter rupture and contrast extravasation. We describe a case in which inadvertent malposition of a central venous catheter led to a high volume extravasation of contrast in the mediastinum in a trauma patient.     

Percutaneous drainage of mediastinal pseudocysts

Percutaneous catheter drainage of a mediastinal pseudocyst was performed in two patients. Access was gained through computed tomography (CT)-guided puncture of the abdominal portion of the pseudocyst in one patient, and a transhepatic-subxiphoid approach was used in the other. Guide wires and catheters were advanced into the mediastinal pseudocysts under CT control. Drainage was technically successful in both patients, with no procedure-related complications. Percutaneous drainage is an alternative to the surgical treatment of symptomatic and nonresolving mediastinal pseudocysts, provided that a safe access route can be found.     

Intractable massive ascites following radical gastrectomy, treatment with local intraperitoneal administration of OK-432 using a unified CT and fluoroscopy system

The case of a patient who developed intractable massive ascites caused by hepatic lymphorrhea derived from surgical injury to the hepatoduodenal ligament is presented. OK-432 was injected intraperitoneally through a catheter advanced to near the hepatoduodenal ligament, so as to expose this site to a high concentration of OK-432. Under ultrasound guidance, it was difficult to reach this site due to massive ascites, and so we performed this procedure under CT and fluoroscopic guidance using a unified CT and angiography system. Subsequently, local administration of OK-432 on five separate occasions resulted in resolution of the ascites. We ascribe this favourable result to the use of this unified CT and angiography system to advance the catheter to the suitable site, making possible the local administration of OK-432.