Split-bolus Technique Research Articles

Diagnostic Utility of Integration of Dynamic Contrast-Enhanced and Dynamic Susceptibility Contrast MR Perfusion Employing Split Bolus Technique in Differentiating High-Grade Glioma.

Background : Despite documented correlation between glioma grades and dynamic contrast-enhanced (DCE) magnetic resonance (MR) perfusion-derived parameters, and its inherent advantages over dynamic susceptibility contrast (DSC) perfusion, the former remains underutilized in clinical practice. Given the inherent spatial heterogeneity in high-grade diffuse glioma (HGG) and assessment of different perfusion parameters by DCE (extravascular extracellular space volume [Ve] and volume transfer constant in unit time [k-trans]) and DSC (rCBV), integration of the two into a protocol could provide a holistic assessment. Considering therapeutic and prognostic implications of differentiating WHO grade 3 from 4, we analyzed the two grades based on a combined DCE and DSC perfusion. Methods : Perfusion sequences were performed on 3-T MR. Cumulative dose of 0.1 mmol/kg of gadodiamide, split into two equal boluses, was administered with an interval of 6 minutes between the DCE and DSC sequences. DCE data were analyzed utilizing commercially available GenIQ software. Results : Of the 41 cases of diffuse gliomas analyzed, 24 were WHO grade III and 17 grade IV gliomas (2016 WHO classification). To differentiate grade III and IV gliomas, Ve cut-off value of 0.178 provided the best combination of sensitivity (88.24%) and specificity (87.50%; AUC: 0.920; p < 0.001). A relative cerebral blood volume (rCBV) of value 3.64 yielded a sensitivity of 70.59% and specificity of 62.50% ( p = 0.018). The k-trans value, although higher in grade III than in grade IV gliomas, did not reach statistical significance ( p = 0.108). Conclusion : Uniqueness of employed combined perfusion technique, treatment naïve patients at imaging, user-friendly postprocessing software utilization, and ability of Ve and rCBV to differentiate between grade III and IV gliomas ( p < 0.05) are the strengths of the present study, contributing to the existing literature and moving a step closer to achieving accurate MR perfusion-based glioma grading.

TEKNIK SPLIT BOLUS TERHADAP INFORMASI ANATOMIS PADA PEMERIKSAAN CT SCAN UROGRAFI

Background : The split bolus technique in CT Scan urography is an intravenous contrast media insertion technique by combining two phases, namely the nephrography phase and the excretory phase in one scan acquisition. In general, the CT Scan urography examination uses 3 phases, non-contrast phase, the nephrographic phase, and the excretory phase. In the role of the split bolus technique, the combination of two phases, namely the nephrographic and excretory phases. The purpose of this study was to explain the split bolus technique and the role of the split bolus technique on anatomical information in CT Scan urography.&#x0D; Methods : This type of descriptive research using a literature review approach. The keywords used are "Split-bolus", "CT Scan Urography". Articles were obtained based on inclusion and exclusion criteria and 7 relevant scientific articles were obtained and were used as literature sources. Data processing through article extraction.&#x0D; Result : The split bolus technique in CT Scan urography examination is a technique of intravenous contrast media that combines two nephrographic and excretory phases in one image acquisition with an average flow rate of 1.5 ml - 3 ml / s. This technique uses a non-ionic iodine contrast medium with a volume of 90 ml - 135 ml and a concentration of 300 mg/ml-370 mg/ml. The role of the split bolus technique on radiation dose and anatomical image information is due to the merging of the two phases in one scan which addresses the anatomy of the urinary system. In addition, the split bolus technique when combined with several reconstructions is able to increase contrast resolution and increase organ enhancement. In this technique, it is better to use the addition of a reconstruction algorithm such as 3D MIP, so that the anatomical image information obtained is more optimal.

CT-Urography study protocol: Split-Bolus technique

CTU represents the natural technical and instrumental evolution of urography. The multidetector technology, withthe possibility of retro-reconstruction of the images, has allowed the direct representation of the excretory tract witha significant reduction in acquisition times, decreasing motion artifacts and increasing the definition of the processedimages. Split-Bolus CT dynamic study allows us to obtain, in a single image acquisition, both the nephrographic andthe renal excretory phases; at the same time, we can obtain information of the parenchymal organs in the abdominalcavity as in the portal/nephrographic phase of a standard CT protocol. The main advantage of Split-Bolus CTUis undoubtedly the significant saving of the radiation dose administered to the patient, related to the reduction inthe number of phases acquired, with a reported diagnostic efficacy comparable to traditional protocols in terms ofimaging quality. The Split Bolus technique has been used in several clinical contexts, such as in the characterizationof focal liver lesions, in acute pulmonary embolism and in polytrauma patients.

CT-Urography study protocol: Split-Bolus technique

CTU represents the natural technical and instrumental evolution of urography. The multidetector technology, with the possibility of retro-reconstruction of the images, has allowed the direct representation of the excretory tract with a significant reduction in acquisition times, decreasing motion artifacts and increasing the definition of the processed images. Split-Bolus CT dynamic study allows us to obtain, in a single image acquisition, both the nephrographic and the renal excretory phases; at the same time, we can obtain information of the parenchymal organs in the abdominal cavity as in the portal/nephrographic phase of a standard CT protocol. The main advantage of Split-Bolus CTU is undoubtedly the significant saving of the radiation dose administered to the patient, related to the reduction in the number of phases acquired, with a reported diagnostic efficacy comparable to traditional protocols in terms of imaging quality. The Split Bolus technique has been used in several clinical contexts, such as in the characterization of focal liver lesions, in acute pulmonary embolism and in polytrauma patients.

Towards the establishment of national imaging practice guidelines: A preliminary study of the basic computed tomography imaging protocols in Ghana

BackgroundThere is a need to harmonize imaging practices in computed tomography (CT) imaging. This study, therefore, investigated the variability of the basic imaging protocols used for CT imaging of common indications in Ghana in order to generate recommendations for the development of national imaging practice guidelines in CT imaging. MethodA cross-sectional study, utilizing a structured online questionnaire, was undertaken (between December 2018 to March 2019) to collect indication-based imaging protocol data (scan coverage, scan series, image quality requirement, slice thickness, reconstruction, scan mode and orientation, required window, AEC usage, scan and breath hold techniques etc.,) across the various CT facilities in the country. Data were analysed and with experts’ input, recommendations were made. ResultsThe imaging protocols used across the CT facilities in the country were largely similar, with a few variabilities for similar examinations. These variabilities were found in scan coverages, series and slice thicknesses. In particular, for a brain tumour examination, 92% of the 25 facilities used both non-contrast and contrast phases while 8% preferred only the IV contrast phase. Seventy percent of all the facilities (n=10) performing pulmonary angiograms in the country also used a two-sequence scan, and others (30%) worked with only the angiogram phase. A majority (89%) of the 19 facilities that were engaged in CT-IVU procedures also used 3-4 scan phases, while 11% preferred a split-bolus technique. None of the facilities employed the low-dose or ultra-low dose protocol for kidney stone examination. ConclusionsThe study's outcome provides an important preliminary roadmap that could lead to the development of imaging practice guidelines to ensure harmonization of imaging practices to improve the protection and safety of patients across the CT facilities.

Split Bolus Method in Computerized Tomography.

The split-bolus method in computed tomography (CT) is the method used in the evaluation of renal dynamic enhancement stages and in the detection of pathologies. When designing the CT urography technique, there are several important options such as single-bolus and split bolus techniques. The single-bolus method consists of three separate post-contrast phases: arterial, nephrographic, and excretory (pyelogram), as a result raising the total radiation dose imparted to patients. On the other hand, in the split-bolus technique, the contrast dose is divided into several separate administrations to obtain the nephrographic and excretory phases simultaneously. With the split-bolus technique, by reducing the radiation dose and the number of phases that the patient will be exposed to, urinary system evaluation and the whole abdomen pathological evaluations can be performed. The device to be used in imaging must be a tomography device with at least 16 Multidetector CT sections. The bolus tracking method is one of the most accurate contrast delivery methods for renal dynamics and the split-bolus technique. Automatic dose calibration is used.

O74: ASSESSING THE USEFULNESS OF THREE-DIMENSIONAL IMAGING AND VIRTUAL REALITY IN SURGICAL PLANNING: A MEDICAL STUDENT LED PILOT STUDY

Abstract Introduction Nephron-sparing surgery is becoming more common as surgical techniques advance. VR and 3D visualisation appear to provide better anatomical understanding in presurgical planning than two-dimensional alone. 3D models may enable greater tissue salvation and fewer complications. 3D model preparation and advancing research is expensive and time consuming. We aim to pilot study led by medical student, create reliable anatomical kidney models and assess usefulness in surgical planning. Method Routine CT urograms were performed on 128 slice scanner using split bolus technique. Medical student segmented and displayed models in VR using 3DSlicer. Radiology registrar and consultant validated models. Two urology surgeons completed qualitative questionnaires. Result We included two patients. Only minor segmentation tweaks by radiologist ensured accurately demonstrated tumors. Tissue contrast quality varied between CT scans complicating segmentation. Both surgeons deemed models helpful in visualising hilar anatomy, predicting bleeding complications, determining laparoscopic/open and partial/full nephrectomy approach. Surgeons prioritised vasculature visualisation over collecting system. Surgeons suggested gauging tumor depth would be useful. Considering 3D printing cost, surgeons agreed VR alone may suffice. Conclusion Surgeons found 3D and VR enabled accurate surgical planning and patient counselling regarding nephrectomy risk. Minor CT protocol recommendations enable easier and more accurate segmentation, without increasing patient's radiation exposure. Annual leave during 8-week summer project reflects case numbers. Since, we've identified more cases to assess surgical parameters against matched cohort. We've begun work for adrenal surgery. It's feasible for medical students with minimal surgical/radiological knowledge to advance this research, gaining valuable experience. Abbrev Virtual Reality(VR), Three-dimensional(3D), Computerised Tomography(CT) Take-home message Three-dimensional imaging and virtual reality may improve surgical planning and patient counselling. Regarding nephrectomy, this could give surgeons the confidence to convert from full nephrectomy to partial nephrectomy approach, improving patient outcome.

CTMS in the study of post-EVAR endoleak in the treatment of aneurysmal dilations

Computed tomography angiography (CTA) has been widely used in diagnostic evaluation of many aortic diseases, but there are not standardized techniques for aortic CTA. The purpose of this study is to compare two methods: biphasic technique and split bolus. A 64-slice CT scanner has been used. There were a total of 28 patients involved in the study. The patients have been divided in two groups: - Group A: 18 patients - Group B: 10 patients The biphasic technique has been used on 18 patients in group A. In this protocol was used a low dose acquisition without contrast medium (CM) and two contrastographic phases with CM. The split bolus technique was performed on 10 patients of group B. 120-140 ml of CM are divided in two boluses. The first bolus of 55-90 ml of CM was injected at a flow of 1,5-2 ml/s, followed by 20ml of physiological solution at a flow of 1,5-2ml/s. After physiological solution the second bolus of 35-60 ml was injected at a flow of 3,5ml/s followed by 20ml of Nacl at a flow of 3,5ml/s. In group A 6 patients had endoleak type I, n=2 endoleak type II, n=8 endoleak type III, n=2 endoleak type IV. (dose of 43.2 mSv). In group B 2 patients had endoleak type I, n= 4 endoleak type II, n=3 endoleak type III and n=1 endoleak type IV. (dose of 16,39 mSv). The biphasic technique has high spatial resolution and contrast resolution, reduction of acquisition times and reduction of artifacts, but an unacceptable a great amount of radiation is involved. The split bolus technique provides results comparable to the biphasic technique but with a lower dose of radiation.

CTMS in the study of post-EVAR endoleak in the treatment of aneurysmal dilations

Computed tomography angiography (CTA) has been widely used in diagnostic evaluation of many aortic diseases, butthere are not standardized techniques for aortic CTA. The purpose of this study is to compare two methods: biphasictechnique and split bolus. A 64-slice CT scanner has been use.There were a total of 28 patients involved in the study.The patients have been divided in two groups:- Group A: 18 patients- Group B: 10 patientsThe biphasic technique has been used on 18 patients in group A. In this protocol was used a low dose acquisitionwithout contrast medium (CM) and two contrastographic phases with CM.The split bolus technique was performed on 10 patients of group B. 120-140 ml of CM are divided in two boluses. Thefirst bolus of 55-90 ml of CM was injected at a flow of 1,5-2 ml/s, followed by 20ml of physiological solution at a flowof 1,5-2ml/s. After physiological solution the second bolus of 35-60 ml was injected at a flow of 3,5ml/s followed by20ml of Nacl at a flow of 3,5ml/s.In group A 6 patients had endoleak type I, n=2 endoleak type II, n=8 endoleak type III, n=2 endoleak type IV. (doseof 43.2 mSv).In group B 2 patients had endoleak type I, n= 4 endoleak type II, n=3 endoleak type III and n=1 endoleak type IV.(dose of 16,39 mSv).The biphasic technique has high spatial resolution and contrast resolution, reduction of acquisition times and reduction of artifacts, but an unacceptable a great amount of radiation is involvedThe split bolus technique provides results comparable to the biphasic technique but with a lower dose of radiation.

PERANAN TEKNIK SPLIT-BOLUS TERHADAP KUALITAS CITRA PADA PEMERIKSAAN MSCT LEHER

Background : According to the theory, Neck MSCT examination were performed using monophasic injection techniques. Split-bolus is an innovative technique that divides intravenous (IV) contrast media into two or three boluses and combines phase images in single scanning. The MSCT split-bolus scan with a combination of parenchymal and vascular enhancement is a valid alternative approach compared to the standard monophasic MSCT protocol. The purpose of this study was to determine the split-bolus technique in neck MSCT examination and its role in the quality of the image.&#x0D; Method : This research is a descriptive qualitative study with a literature review study method. Data is collected by the documentation method. The electronic database was searched using the keywords "head and neck" AND ("contrast" OR "injection") AND ("Split bolus" OR "Biphasic Contrast" OR "Dual bolus" OR "Double bolus" OR "Multi-phase" OR "Quadruple-Phase"). The inclusion criteria used were a research article on a split-bolus technique in a single scan on MSCT neck examination. Three articles met the inclusion criteria. Data analysis was performed using the annotated bibliography method.&#x0D; Result : The results of this study indicate that the contrast media used in the MSCT examination of the neck with a split-bolus technique are non-ionic iodine contrast media with a total volume of 80-100 mL and a concentration of 300-370 mg / mL. Contrast media injection is done by dividing contrast media in the first and second boluses using a ratio of 3 : 2 or 1 : 1 of the total volume of contrast media followed by saline injection. The flow rate used is 2 - 3 mL / s with a fixed delay time between 70 - 120 seconds. The split - bolus techniques have a role in contrast resolution of image quality. The image quality produced on neck MSCT examination using split bolus technique can increase vaskular and tumor enhancement without reducing parenchymal enhancement and lesions. In a patient with metastasis, this technique can reduce artifacts due to excessive contrast media in the arteries and veins so the lymph nodes appear more clearly.&#x0D; Conclusion : Based on the result, the split - bolus techniques have a role in contrast resolution of image quality.&#x0D;

CT Protocol Optimization in Trauma Imaging: A Review of Current Evidence

Trauma constitutes a social and a clinical problem. The CT protocol to be adopted in polytrauma patients is still not standardized across institutions. A variety of protocols can be found in the available literature, which differ from each other in timing acquisition and number of phases. Even if multiple recent studies are investigating the role of split bolus technique, multiphasic protocol has been shown to be associated with early detection and adequate characterization of vascular injuries, so it should be still considered as the “best” CT protocol for the assessment of high-energy trauma patients. The article provides a review on the currently available literature on the CT protocols adopted in polytraumatized patients.

A split bolus technique in TAVI CT increases accuracy of LAA thrombus detection and reduces the requirement for TOE

Category: Cardiac.

Computed Tomography Urography: Comparison of Image Quality and Radiation Dose between Single- and Split-Bolus Techniques

In this study, we aimed to compare the split-bolus and single-bolus computerised tomography (CT) urography and determine if this offers a reduction in radiation dose without compromising image quality. A retrospective evaluation was performed on 88 patients undergoing split-bolus CT urography and this was compared to a control group of 101 consecutive patients undergoing single-bolus CT urography. A radiation dose analysis was performed on each subject. Subjects with urinary bladder lesions, hydronephrosis, renal masses or cysts >3 cm in diameter were excluded. All images were classified according to image quality by 2 consultant radiologists. Opacification of the renal parenchyma, pelvicalyceal system, proximal ureters and urinary bladder were comparable between the 2 techniques, whilst image quality of the middle and distal third of the ureters was better using the split-bolus technique. The mean dose length product (DLP) for the single-bolus technique was 1324.1 mGy-cm, whilst that of the split-bolus technique was 885.7 mGy-cm. The mean effective dose reduction was calculated to be 31.1% between the 2 groups. The split-bolus technique gives a reduced radiation dose without compromising image quality. The associated reduction in images is beneficial for data storage and reporting efficiency. As such, our department will adopt the split-bolus technique for young, low-risk patients.

CT-Urography: Comparison of different methods for increasing the intra-abdominal pressure

Objective: Investigating the influence of increasing the intraabdominal pressure by Valsalva maneuvers and/or abdominal compression to reach best visualization of the entire urinary tract in computed tomography urography (CTU).Methods: After split-bolus technique, Valsalva maneuvers, compression or a combination of both were applied in 60 patients before late phase images were acquired. The degree of opacification and distension of three segments of the urinary tract were evaluated.Results: After split-bolus CT no significant difference among the groups regarding distention and opacification. A significant increase in distension and opacification was found during Valsalva and the combination of Valsalva and compression.Conclusions: A CTU protocol including a late phase scan with prior application of compression, Valsalva maneuvers or a combination of both showed beneficial effects for the distension and opacification, a significant difference was found by taking location as a covariate.

One-phase Split-bolus CT Urography – a Novel Approach To Reduce Radiation Dose in Diagnostics of Congenital Anomalies of Kidneys and Urinary Tract in Children

BackgroundLow-dose CT Urography (LD-CTU) has become a standard procedure in urinary tract abnormalities in children, especially when MR Urography is not available. Standard one-phase CTU is performed in excretory phase. There is also a split-bolus technique, which combines two or even three phases during one scan and provides more clinical information without higher radiation exposure. It can be implemented for congenital anomalies of kidneys and urinary tract (CAKUT) in children, however, this application is not deeply discussed in scientific literature. Aim of this publication is to present the protocol and determine the role of LD-CTU in diagnostic imaging of CAKUT in children.Material and methodsClose to 300 CTUs in children were performed as a standard of care during the last 6 years in our Department. Diagnostic accuracy in suspected CAKUT was analyzed, depending on applied protocol − standard excretory CTU, multiphase CTU and two different one-phase split-bolus CTU protocols.ResultsVisualization of the urinary tract was adequate in all study protocols. However, more clinically significant information was received in vascular-excretory protocol, including vascular and renal anatomy. Radiation exposure was similar or even lower than in other study protocols.ConclusionsOne-phase split-bolus CTU protocol is a novel approach in low-dose diagnostic imaging of CAKUT in children. Combination of vascular and excretory phases has been shown as very effective technique, especially in comprehensive anatomical assessment of the abnormality and qualification to surgical intervention.

Imaging algorithms and CT protocols in trauma patients: survey of Swiss emergency centers.

To identify imaging algorithms and indications, CT protocols, and radiation doses in polytrauma patients in Swiss trauma centres. An online survey with multiple choice questions and free-text responses was sent to authorized level-I trauma centres in Switzerland. All centres responded and indicated that they have internal standardized imaging algorithms for polytrauma patients. Nine of 12 centres (75%) perform whole-body CT (WBCT) after focused assessment with sonography for trauma (FAST) and conventional radiography; 3/12 (25%) use WBCT for initial imaging. Indications for WBCT were similar across centres being based on trauma mechanisms, vital signs, and presence of multiple injuries. Seven of 12 centres (58%) perform an arterial and venous phase of the abdomen in split-bolus technique. Six of 12 centres (50%) use multiphase protocols of the head (n = 3) and abdomen (n = 4), whereas 6/12 (50%) use single-phase protocols for WBCT. Arm position was on the patient`s body during scanning (3/12, 25%), alongside the body (2/12, 17%), above the head (2/12, 17%), or was changed during scanning (5/12, 42%). Radiation doses showed large variations across centres ranging from 1268-3988mGy*cm (DLP) per WBCT. Imaging algorithms in polytrauma patients are standardized within, but vary across Swiss trauma centres, similar to the individual WBCT protocols, resulting in large variations in associated radiation doses. • Swiss trauma centres have internal standardized imaging algorithms for trauma patients • Whole-body CT is most commonly used for imaging of trauma patients • CT protocols and radiation doses vary greatly across Swiss trauma centres.

Endoleak detection using single-acquisition split-bolus dual-energy computer tomography (DECT)

ObjectivesTo assess a single-phase, dual-energy computed tomography (DECT) with a split-bolus technique and reconstruction of virtual non-enhanced images for the detection of endoleaks after endovascular aneurysm repair (EVAR).MethodsFifty patients referred for routine follow-up post-EVAR CT and a history of at least one post-EVAR follow-up CT examination using our standard biphasic (arterial and venous phase) routine protocol (which was used as the reference standard) were included in this prospective trial. An in-patient comparison and an analysis of the split-bolus protocol and the previously used double-phase protocol were performed with regard to differences in diagnostic accuracy, radiation dose, and image quality.ResultsThe analysis showed a significant reduction of radiation dose of up to 42 %, using the single-acquisition split-bolus protocol, while maintaining a comparable diagnostic accuracy (primary endoleak detection rate of 96 %). Image quality between the two protocols was comparable and only slightly inferior for the split-bolus scan (2.5 vs. 2.4).ConclusionsUsing the single-acquisition, split-bolus approach allows for a significant dose reduction while maintaining high image quality, resulting in effective endoleak identification.Key Points• A single-acquisition, split-bolus approach allows for a significant dose reduction.• Endoleak development is the most common complication after endovascular aortic repair (EVAR).• CT angiography is the imaging modality of choice for aortic aneurysm evaluation.

Split-Bolus Single-Pass Multidetector-Row CT Protocol for Diagnosis of Acute Pulmonary Embolism.

Background:Currently computed tomography pulmonary angiography (CTPA) has become a widely accepted clinical tool in the diagnosis of acute pulmonary embolism (PE).Objectives:To report split-bolus single-pass 64-multidetector-row CT (MDCT) protocol for diagnosis of PE.Patients and Methods:MDCT split-bolus results in 40 patients suspicious of PE were analyzed in terms of image quality of target pulmonary vessels (TPVs) and occurrence and severity of flow-related artifact, flow-related artifact, false filling defect of the pulmonary veins and beam hardening streak artifacts. Dose radiation to patients was calculated.Results:MDCT split-bolus protocol allowed diagnostic images of high quality in all cases. Diagnosis of PE was obtained in 22 of 40 patients. Mean attenuation for target vessels was higher than 250 HU all cases: 361 ± 98 HU in pulmonary artery trunk (PAT); 339 ± 93 HU in right pulmonary artery (RPA); 334 ± 100 HU in left pulmonary artery (LPA). Adequate enhancement was obtained in the right atrium (RA):292 ± 83 HU; right pulmonary vein (RPV): 302 ± 91 HU, and left pulmonary vein (LPV): 291 ± 83 HU. The flow related artifacts and the beam hardening streak artifacts have been detected respectively in 4 and 25 patients. No false filling defect of the pulmonary veins was revealed.Conclusion:MDCT split-bolus technique by simultaneous opacification of pulmonary arteries and veins represents an accurate technique for diagnosis of acute PE, removes the false filling defects of the pulmonary veins, and reduces flow related artifacts.

Split bolus technique in polytrauma: a prospective study on scan protocols for trauma analysis.

For the evaluation of severely injured trauma patients a variety of total body computed tomography (CT) scanning protocols exist. Frequently multiple pass protocols are used. A split bolus contrast protocol can reduce the number of passes through the body, and thereby radiation exposure, in this relatively young and vitally threatened population. To evaluate three protocols for single pass total body scanning in 64-slice multidetector CT (MDCT) on optimal image quality. Three total body CT protocols were prospectively evaluated in three series of 10 consecutive trauma patients. In Group A unenhanced brain and cervical spine CT was followed by chest-abdomen-pelvis CT in portovenous phase after repositioning of the arms. Group B underwent brain CT followed without arm repositioning by a one-volume contrast CT from skull base to the pubic symphysis. Group C was identical to Group A, but the torso was scanned with a split bolus technique. Three radiologists independently evaluated protocol quality scores (5-point Likert scale), parenchymal and vascular enhancement and artifacts. Overall image quality was good (4.10) in Group A, more than satisfactory (3.38) in Group B, and nearly excellent (4.75) in Group C (P < 0.001). Interfering artifacts were mostly reported in Group B in the liver and spleen. In single pass total body CT scanning a split bolus technique reached the highest overall image quality compared to conventional total body CT and one-volume contrast CT.

Upper urinary tract tumors: how does the contrast enhancement measured in a split-bolus CTU correlate to histological staging?

Computed tomography urography (CTU) is used widely in the work-up of patients with symptoms of urinary tract lesions. Preoperative knowledge of whether a tumor is invasive or non-invasive is important for the choice of surgery. So far there are no studies about the distinction of invasive and non-invasive tumors in ureter and renal pelvis based on the enhancement measured with Hounsfield Units. To examine the value of CTU using split-bolus technique to distinguish non-invasive from invasive urothelial carcinomas in the upper urinary tract. Patients who underwent nephroureterectomy between 2006 and 2011 and who had split-bolus CTU prior to surgery were included. The images were available electronically. The attenuation values before and after administration of iodine-based contrast media were measured. The radiology, patient, and pathology records were reviewed. Of the 158 patients who underwent unilateral nephroureterectomy 69 fulfilled the inclusion criteria. Histopathological examination revealed 31 patients with non-invasive and 38 with invasive urothelial carcinoma. Neither absolute attenuation nor change in attenuation values obtained at CTU could distinguish between invasive and non-invasive lesions. No patients had a CTU within the last year before the examination that resulted in surgery. A split-bolus CTU cannot distinguish between invasive and non-invasive urothelial tumors in the upper urinary tract, but the examination is useful to diagnose a tumor in the renal pelvis and the ureter.