CT urography: how to optimize the technique

Cheng, Karen Y.; Cassidy, Fiona; Aganović, Lejla; Taddonio, Michael; Vahdat, Noushin

doi:10.1007/s00261-019-02111-2

Cited by 19 publications

(20 citation statements)

References 60 publications

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“…CT scans have the advantages of short imaging time, few contraindications and high accuracy and are currently the most commonly used examination method for preoperative diagnosis and staging of RCC [ 5 , 6 ]. For the best diagnosis and most accurate staging, the reference standard for dedicated multiphase renal cell carcinoma imaging consists of unenhanced phase, corticomedullary phase, nephrographic phase and excretory phase scans [ 7 ]. Multiphase scans can provide sufficient diagnostic information, including the baseline CT density value of the tumours, the degree and characteristics of lesion enhancement, the relationship between tumours and arteries as well as the extent of renal pelvis involvement [ 6 ].…”

Section: Introductionmentioning

confidence: 99%

Utilisation of virtual non-contrast images and virtual mono-energetic images acquired from dual-layer spectral CT for renal cell carcinoma: image quality and radiation dose

Zhang

et al. 2022

Insights Imaging

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Background Renal cell carcinoma (RCC) is the most common renal malignant tumour. We evaluated the potential value and dose reduction of virtual non-contrast (VNC) images and virtual monoenergetic images (VMIs) from dual-layer spectral CT (DL-CT) in the diagnosis of RCC. Results Sixty-two patients with pathologically confirmed RCC who underwent contrast-enhanced DL-CT were retrospectively analysed. For the comparison between true non-contrast (TNC) and VNC images of the excretory phase, the attenuation, image noise, signal-to-noise ratio (SNR) and subjective image quality of tumours and different abdominal organs and tissues were evaluated. To compare corticomedullary phase images and low keV VMIs (40 to 100 keV) from the nephrographic phase, the attenuation, image noise, SNR and subjective lesion visibility of the tumours and renal arteries were evaluated. For the tumours, significant differences were not observed in attenuation, noise or SNR between TNC and VNC images (p > 0.05). For the abdominal organs and tissues, except for fat, the difference in attenuation was 100% within 15 HU and 96.78% within 10 HU. The subjective image quality of TNC and VNC images was equivalent (p > 0.05). The attenuation of lesions in 40 keV VMIs and renal arteries in 60 keV VMIs were similar to those in the corticomedullary images (p > 0.05). The subjective lesion visibility in low keV VMIs is slightly lower than that in the corticomedullary images (p < 0.05). Using VNC and VMIs instead of TNC and corticomedullary phase images could decrease the radiation dose by 50.5%. Conclusion VNC images and VMIs acquired from DL-CT can maintain good image quality and decrease the radiation dose for diagnosis of RCC.

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Section: Introductionmentioning

confidence: 99%

Utilisation of virtual non-contrast images and virtual mono-energetic images acquired from dual-layer spectral CT for renal cell carcinoma: image quality and radiation dose

Zhang

et al. 2022

Insights Imaging

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“…An unenhanced phase is used to detect stones, calcifications, hemorrhages, clots, and to measure the attenuation coefficients of the renal and urothelial masses 14 . A corticomedullary phase, occurring between 30 and 40s after contrast medium administration, is used to evaluate suspected vascular abnormalities or arterial enhancement 14,15 , while a nephrographic phase, acquired 90-110 s after contrast medium administration, improves detection and characterization of renal lesions 14 . The excretory phase obtained 8-12 min after contrast agent administration, assesses the abnormalities of the urothelium with the distension and the opacification of the collecting systems, ureters and bladder 15 .…”

Section: Discussionmentioning

confidence: 99%

A Study on Ureteric Abnormalities in Single Contrast Bolus CT Urography at A Tertiary Care Centre

Varma

Titare²,

Kaginalkar³

2023

ijmsdr

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Introduction: CT urography is an imaging technique in which the i.v contrast is injected and phases of CT scan are taken to study the entire urinary system. It has essentially replaced intravenous urography (IVU) in most imaging practices. CT Urography has evolved as an ideal imaging tool for comprehensive imaging assessment of patients with flank pain, malignancies, hematuria, trauma, renal calculi, suspected congenital malformations and in various clinical settings. Other CT advantages include the use of multiplanar reconstruction (MPR), curved planar reformatted images, maximum intensity projection (MIP) and three-dimensional (3D) reconstruction which gives valuable information to the clinician about the extent of the lesions and helps in management. Aim: To study various types of ureteric abnormalities in CT Urography in various clinical presentation. Materials and methods: This is a tertiary hospital based observational Descriptive Cross sectional study conducted on 360 patients referred for CT Urography with Clinical Signs & Symptoms of urinary tract abnormalities, having ureteric imaging abnormalities. Siemens somatum High Definition 128 slice CT scanner was used for single bolus CT urography. Results: Males were more as compared to females with age group 31 to 50 years (44.4%). Abdominal pain with urinary complaints was seen in maximum number of patients (203 cases- 56.4%). Urinary complaints in known abdomino-pelvic malignancies was seen in 18% cases. 285 patients had obstructive urography findings like hydronephrosis or hydroureter, and 75 cases had non obstructive findings like ureteral filling defects due to calculi, clots, etc or abnormal ureteric course or only congenital abnormality. Most hydroureter cases were secondary to obstructive calculus followed by obstruction by external malignant mass. Conclusion: This study outlines the most common ureteric abnormalities in patients referred for CT urography which were mostly obstructive findings most cases were secondary to obstructive calculus followed by obstruction by external malignant mass. The non obstructive findings like ureteral filling defects were due to calculi, clots, etc or abnormal ureteric course or only congenital abnormalities. Delayed phase of CT urography can also be applied in Contrast CT study of abdomen & Pelvic scans on case to case basis to study ureteric involvements & pathologies.

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“…For example, a recent study evaluating DLPs associated with CTU across 14 countries found a median of 1740 mGy•cm and 25th and 75th percentiles of 869 and 2943 mGy•cm, respectively [15]. We limited the radiation dose in young patients by applying the split bolus protocol to patients <50 years old, which is similar to the 40-year old cutoff applied by Cheng et al [7]. We also limited the radiation in young patients by having the radiologist check the unenhanced phase prior to contrast media injection, as hematuria in young patients is often caused by urinary tract calculi [20].…”

Section: Radiation Dose Of Ctumentioning

confidence: 99%

“…The most common CTU technique acquires three separate phases or CT acquisitions at the following timepoints: An unenhanced phase prior to contrast media injection; a nephrographic phase acquired 80-120 s after intravenous (IV) injection of contrast media; and an excretory phase, acquired several minutes after contrast media injection, during which contrast media is excreted by the kidneys and opacifies the upper urinary tracts [6]. In this technique, the entire contrast media volume is injected as a single bolus; the advantage is that all of the contrast bolus contributes to the nephrographic and excretory phases, at the expense of three separate CT acquisitions, which results in higher ionizing radiation dose to the patient [6,7]. The second most common CTU technique is the split-bolus technique, where the nephrographic and excretory phases are acquired at the same time, in order to eliminate CT acquisition, and thereby, reduce the radiation dose by approximately one-third.…”

Section: Introductionmentioning

confidence: 99%

Split vs. Single Bolus CT Urography: Comparison of Scan Time, Image Quality and Radiation Dose

2021

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The purpose of this study was to compare the scan time, image quality and radiation dose of CT urograms (CTU) using a split vs. single bolus contrast media injection technique. A total of 241 consecutive CTUs performed between August 2019-February 2020 were retrospectively reviewed. There were three study groups: Group 1, <50 years old, 50/80 cc split-bolus administered at 0 and 700 s post initiation of injection, with combined nephrographic and excretory phases; group 2, ≥50 years old, same split-bolus protocol; and group 3, ≥50 years old, 130 cc single bolus injection, with nephrographic and excretory phases acquired at 100 s and 460 s post injection initiation. The recorded data elements were scan time, number of excretory phases, imaging quality based on opacification of the urinary collecting system (<50%, 50–75%, 75–100%), and dose-length product (DLP). Associations between group and categorical variables were assessed (Chi-square); mean scan time and DLP were compared (one-way ANOVA). Following analysis, proportionally fewer CTUs required a repeat excretory phase in group 3 (32/112, 28.6%) than in groups 1 (25/48, 52.1%) and 2 (37/80, 46.3%) (p = 0.006). Mean scan time was significantly lower in group 3 (678 s) than in groups 1 (1046 s) and 2 (978 s) (p < 0.0001). There was no association between groups and image quality (p = 0.13). DLP was higher in group 3 (1422 ± 837 mGy·cm) than in groups 1 (1041 ± 531 mGy·cm) and 2 (1137 ± 646 mGy·cm) (p = 0.003). In conclusion, single bolus CTU resulted in significantly fewer repeat phases and faster scan time at the expense of a slightly higher radiation dose.

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CT urography: how to optimize the technique

Cited by 19 publications

References 60 publications

Utilisation of virtual non-contrast images and virtual mono-energetic images acquired from dual-layer spectral CT for renal cell carcinoma: image quality and radiation dose

Utilisation of virtual non-contrast images and virtual mono-energetic images acquired from dual-layer spectral CT for renal cell carcinoma: image quality and radiation dose

A Study on Ureteric Abnormalities in Single Contrast Bolus CT Urography at A Tertiary Care Centre

Split vs. Single Bolus CT Urography: Comparison of Scan Time, Image Quality and Radiation Dose

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