Acta Radiologica

Gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) can be used as an imaging-based liver function test. This study aims to further corroborate its validity.

To compare Gd-EOB-DTPA-enhanced MRI as an imaging-based liver function test with the ¹³C-methacetin breath test.

Fifty-three patients who underwent Gd-EOB-DTPA-enhanced MRI T1 relaxometry before and 20 min after intravenous Gd-EOB-DTPA administration as well as a ¹³C-methacetin breath test (LiMAx test) were retrospectively analyzed. T1 relaxation times of liver parenchyma, total liver volume (TLV), and functional liver volume (FLV) were determined. Pearson correlations, multiple linear regression analysis, and receiver operating characteristic curve analysis were performed with indices derived from T1 relaxometry, liver volumetry, and laboratory parameters to identify the best predictor of liver function as determined by the LiMAx test.

T1 reduction rate (T1 RR), T1 RR × TLV, T1 RR × FLV, and T1 relaxation time 20 min after intravenous Gd-EOB administration showed a statistically significant correlation with LiMAx and discriminatory capacity between patients with LiMAx of > and < 315 µg/kg/h. Of the indices investigated, T1 RR showed the best discriminatory capacity and proved to be the only statistically significant parameter in multiple linear regression analysis.

Gd-EOB-DTPA-enhanced MRI as an imaging-based liver function test also correlates with the LiMAx test which in turn reflects cytochrome P450 function. The T1 reduction rate of the liver on Gd-EOB-DTPA-enhanced MRI allows prediction of liver function as determined by the LiMAx test both for 1.5 and 3.0 T.

Magnetic resonance imaging (MRI) with hepatocyte specific contrast has the highest sensitivity for colorectal liver metastases but comes at high costs and long examination times.

To evaluate if preoperative detection of colorectal liver metastases with less resource-consuming diffusion-weighted imaging (DWI) alone or in combination with multidetector computed tomography (MDCT) can compete with gadolinium-etoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MRI.

Forty-four patients with 123 colorectal liver metastases received MDCT and Gd-EOB-DTPA-enhanced MRI including DWI before liver resection for colorectal liver metastases. Five image sets were evaluated by two radiologists. The DWI set consisted of DWI, ADC map, coronal, axial T2-weighted single-shot sequences. The DWI-T2F set contained additionally respiratory-triggered T2-weighted TSE-SPIR sequences. The MDCT set consisted of four-phase MDCT, the MDCT-DWI set also contained DWI. The CE-MRI set contained all MRI sequences including Gd-EOB-DTPA. Reference standards was histopathology and follow-up.

CE-MRI set had highest sensitivity (P ≤ 0.013) with 95% compared to 72%, 73%, 73%, and 87% the for DWI set, DWI-T2W-FS set, MDCT set, and MDCT-DWI set, respectively. The CE-MRI set had the highest sensitivity (P≤0.012) for colorectal liver metastases <10 mm with 87% compared to 55%, 52%, 23%, and 58% for the DWI set, DWI-T2W-FS set, MDCT set, and MDCT-DWI set, respectively. The MDCT-DWI set improved sensitivity overall and in size-dependent subgroup analyses compared to the MDCT set (P ≤ 0.031). The MDCT-DWI set showed the highest specificity of 98% followed by 98%, 98%, 95%, and 88% for the DWI set, DWI-T2W-FS set, MDCT set, and CE-MRI set, respectively.

The less resource and time-consuming DWI sets are inferior to Gd-EOB-DTPA-enhanced MRI for the detection of colorectal liver metastases. Gd-EOB-DTPA-enhanced MRI with its excellent sensitivity should be the preferred preoperative modality when meticulous lesion identification is essential. Combination of DWI with MDCT improved significantly sensitivity compared to each modality alone.

Computer-aided detection software for automated breast ultrasound has been shown to have potential in improving the accuracy of radiologists. Alternative ways of implementing computer-aided detection, such as independent validation or preselecting suspicious cases, might also improve radiologists’ accuracy.

To investigate the effect of using computer-aided detection software to improve the performance of radiologists by validating findings reported by radiologists during screening with automated breast ultrasound.

Unilateral automated breast ultrasound exams were performed in 120 women with dense breasts that included 60 randomly selected normal exams, 30 exams with benign lesions, and 30 malignant cases (20 mammography-negative). Eight radiologists were instructed to detect breast cancer and rate lesions using BI-RADS and level-of-suspiciousness scores. Computer-aided detection software was used to check the validity of radiologists' findings. Findings found negative by computer-aided detection were not included in the readers’ performance analysis; however, the nature of these findings were further analyzed. The area under the curve and the partial area under the curve for an interval in the range of 80%–100% specificity before and after validation of computer-aided detection were compared. Sensitivity was computed for all readers at a simulation of 90% specificity.

Partial AUC improved significantly from 0.126 (95% confidence interval [CI] = 0.098–0.153) to 0.142 (95% CI = 0.115–0.169) (P = 0.037) after computer-aided detection rejected mostly benign lesions and normal tissue scored BI-RADS 3 or 4. The full areas under the curve (0.823 vs. 0.833, respectively) were not significantly different (P = 0.743). Four cancers detected by readers were completely missed by computer-aided detection and four other cancers were detected by both readers and computer-aided detection but falsely rejected due to technical limitations of our implementation of computer-aided detection validation. In this study, validation of computer-aided detection discarded 42.6% of findings that were scored BI-RADS ≥3 by the radiologists, of which 85.5% were non-malignant findings.

Validation of radiologists’ findings using computer-aided detection software for automated breast ultrasound has the potential to improve the performance of radiologists. Validation of computer-aided detection might be an efficient tool for double-reading strategies by limiting the amount of discordant cases needed to be double-read.

No evidence-based guidelines regarding optimal breast compression in mammography exist, neither for standard digital mammography nor for digital breast tomosynthesis.

To compare breast compression parameters and mean glandular dose in a randomized controlled trial with digital mammography versus digital breast tomosynthesis.

We used information from 21,729 women aged 50–69 years, who participated in the To-Be trial, as part of BreastScreen Norway, 2016–2017. Information was obtained from the DICOM header and by assessing the images in an automated software for density estimation (VolparaDensity). Using linear regression, we investigated the effect of screening technique on breast compression parameters; compression force (N), compression pressure (kPa), and compressed breast thickness (mm), and mean glandular dose (mGy), by view (craniocaudal [CC] and mediolateral oblique [MLO]). We adjusted for age, breast volume and fibroglandular volume.

A total of 11,056 (50.9%) women were screened with digital mammography and 10,673 (49.1%) with digital breast tomosynthesis. Adjusted regression analysis showed that women undergoing digital mammography received higher compression forces than women undergoing digital breast tomosynthesis (CC: –4.7 N; MLO: –1.1 N, P < 0.001 for both), higher compression pressure (CC: –1.0 k Pa; MLO: –0.1 kPa, P < 0.001 for both), and higher values of compressed breast thickness in the MLO view (–0.3 mm, P = 0.02). The women undergoing digital mammography received a lower mean glandular dose than women undergoing digital breast tomosynthesis ([+]0.06 mGy, P < 0.001).

Women undergoing digital breast tomosynthesis received lower compression force, compression pressure, and compressed breast thickness in MLO view, compared to women undergoing digital mammography. Further studies should investigate the impact of breast compression on image quality, screening outcome, and radiation dose for digital mammography and digital breast tomosynthesis in order to establish evidence-based guidelines for breast compression.

To date, only a few data have demonstrated the safety of iodinated contrast media for cerebral angiography.

To assess contrast-related adverse events after cerebral angiography using iobitridol.

A total of 790 patients who underwent cerebral angiography at three tertiary hospitals in the Republic of Korea between November 2017 and October 2018 were prospectively enrolled in this study. We interviewed all patients and recorded their symptoms before they left the interventional clinic after the angiography procedure and during the seven-day follow-up visit. The primary endpoints were acute (within 1 h) and delayed (1 h–7 days) adverse events associated with iobitridol injection. We also visually graded the radiographic density and image quality as secondary endpoints.

Acute adverse events were more common than delayed adverse events. Most adverse events were either mild (96.5%) or moderate (3.45%). Among the contrast-related adverse events, feeling of warmth (59.1%) and altered taste (17.5%) were the most common acute events, whereas headache (41.9%) and allergic skin reactions (20.0%) were the most common delayed events. All cerebral angiography showed optimal density and good/excellent image quality.

The findings of this study suggest that iobitridol is a safe and effective iodinated contrast medium for use in cerebral angiography.

Due to their crucial role in many diagnostic processes, a considerable number of papers in non-radiological medical journals contain images. We noticed that radiologists are seldom mentioned as co-authors.

To investigate how often radiologists are involved as co-authors and to measure the influence of their involvement on the choice and quality of the illustrations and captions.

We queried PubMed for papers in English with the search string “case report” in the title, examined them for the presence of radiological images, and excluded those published in radiological journals. We developed a scoring system, containing objective and subjective qualification criteria. In addition, we checked if a radiologist was involved as co-author, or mentioned in the Acknowledgments section. We performed a statistical analysis to check if the involvement of a radiologist had a significant effect on the overall quality of the case report.

In 21% (45/218) of the papers, a radiologist was mentioned as co-author and in 3% (7/218) a radiologist was mentioned in the acknowledgments. In 76% (166/218), radiologists were neither involved as co-authors, nor mentioned in acknowledgments. We found statistically significant quality differences between these three groups (P < 0.001).

This study indicated that the quality of case reports can be improved when radiologists are involved in the preparation and publication of papers containing imaging studies.

The 8th edition of tumor, node, metastasis (TNM) classification incorporates depth of invasion evaluation in the staging of oral cavity squamous cell carcinoma, since it is a predictor of nodal metastasis and an independent prognostic factor. Although the histopathological definition of depth of invasion is clear, an accurate method for its radiological assessment has not yet been validated.

To investigate the role of MRI-derived depth of invasion evaluation in staging oral tongue squamous cell carcinoma and to assess the inter-reader agreement and the radiological–pathological correlation.

We retrospectively reviewed 43 patients with oral tongue squamous cell carcinoma who underwent preoperative MRI. The MRI-derived depth of invasion was measured by two radiologists, each with a different degree of experience in head and neck imaging. The pathological depth of invasion was recorded from histopathological reports. The inter-reader and the radiological–histopathological correlations for the depth of invasion were evaluated with Bland–Altman plots, the intraclass correlation coefficients (ICC), and the paired samples test; agreements for T staging were assessed using the Kappa coefficient.

Inter-reader reliability was excellent for the MRI-derived depth of invasion (ICC = 0.91), very good between MRI-derived depth of invasion and pathological depth of invasion (ICC = 0.89 for the experienced reader, 0.86 for the inexperienced reader). Both readers reached a good agreement regarding T staging (kappa value = 0.70). Furthermore, the agreement between radiological and pathological T staging was good (kappa value = 0.74 for the experienced reader, 0.60 for the inexperienced reader).

MRI-derived depth of invasion should be measured in the pretreatment assessment of oral tongue squamous cell carcinoma as it has an excellent inter-reader reliability and nearly excellent radiological–pathological correlation.

Percutaneous transluminal angioplasty is established as the first-line vascular procedure in patients with lower extremity artery disease.

We aimed to evaluate the technical and clinical effectiveness of percutaneous transluminal angioplasty in the management of ischemic foot ulcers.

All consecutive patients presenting with a foot ulcer at the outpatient vascular surgery clinic of our hospital between June 2009 and June 2015 were evaluated using foot pulse assessment, ankle-brachial index, and duplex scanning. If non-invasive parameters suggested lower extremity artery disease, CT angiography and/or digital subtraction angiography were performed and a percutaneous transluminal angioplasty was carried out when feasible during the same session. All patients were followed until healing, amputation, death, or for at least two years. Short- and long-term clinical success was evaluated based on ulcer size and appearance. Patients with worsening ulcers after percutaneous transluminal angioplasty underwent bypass grafting or amputation.

Percutaneous transluminal angioplasty was performed in 161 patients (100%) with stenoses > 50%, including cases lesions > 10 cm and/or multiple/calcified lesions, 144 of which completed the study. In 88 (61.2%) patients, percutaneous transluminal angioplasty was performed in the suprapopliteal axis exclusively, in 10 (6.8%) patients in the infrapopliteal axis only, and in 46 (31.9%) in both levels. Percutaneous transluminal angioplasty was technically successful in 141 (98%) patients. After 3.1 years, the rate of healing was 68%, limb salvage 88%, overall survival 69.5%, and amputation-free survival 64%.

Our data suggest that percutaneous transluminal angioplasty for ischemic foot ulceration treatment is in the majority of patients feasible, effective, and safe with high rates of healing and limb salvage.

The study describes the difference of pain reduction in interlaminar and transforaminal injections.

To compare treatment outcomes after interlaminar versus transforaminal epidural steroid injections in patients with disc herniations at the level L3/4–L5/S1 and analyze associated magnetic resonance imaging (MRI) findings.

This retrospective comparative effectiveness outcome study included 198 patients with computed tomography (CT)-guided interlaminar (n = 99) or transforaminal (n = 99) epidural injections with particulate steroids. Pain levels at baseline and one day, one week, and one month after injection were assessed using the 11-point Numerical Rating Scale for Pain. Overall improvement was assessed after one day, one week, and one month using the Patients Global Impression of Change. MRI analysis was performed by two radiologists. Student’s t-test, Chi-square test, and Fisher’s exact test were calculated.

Baseline pain scores were equal for interlaminar and transforaminal injections (6.23, SD = 2.10 vs. 5.84, SD = 2.02; P = 0.18). There were no significant differences in improvement between the interlaminar and transforaminal approach of epidural steroid injections after one day (30.5% vs. 21.2%, P = 0.432), one week (41.7% vs. 40.8%, P = 1.000), and one month (53.3% vs. 43.9%, P = 0.322), but there was a trend towards better effect of interlaminar injections at one day and one month. The change in Numerical Rating Scale for Pain scores showed no significant differences between the two cohorts after one day, one week, and one month (P ≥ 0.115). None of the MR findings predicted a better or worse outcome (P ≥ 0.171).

Interlaminar and transforaminal injections with particulate corticosteroids were equally effective, with a non-significant advantage of interlaminar injections at one day and one month. None of the MR findings were associated with treatment outcomes.

There are many underlying accelerator factors for chondromalacia and one of the well-known factors is patellar malalignment.

To evaluate the relationship between early-onset chondromalacia and patellar position; and, second, to evaluate the value of patellar malalignment criteria.

Patients aged 18–40 years with advanced chondromalacia were included. For comparison, a control group was defined with the same number of individuals of the same mean age. The magnetic resonance imaging (MRI) sagittal view with the greatest patellar length was used to obtain the patellar height measurement with the Insall-Salvati index. For the remaining three indices—modified Insall-Salvati, Caton-Deschamps, and Blackburne-Pell—a sagittal view with the greatest patellar articular surface was used. Discordance was defined as contradiction with the measured index and the other three indices.

Both patella alta and baja were found to be predisposing factors for chondromalacia. Modified Insall-Salvati index was the most concordant measurement to define patella alta.

Both patella alta and patella baja were found to predispose to chondromalacia. Patella baja is rare, which may explain why it is not often mentioned as a predisposing factor. The modified Insall-Salvati index ratio was the best patella alta indicator that showed chondral status, more than patellar placement, and was more concordant with the other indices. Blackburne-Pell had the second highest number and ratio of discordance. BP cannot be optimally calculated because deciding the location of the tibial plateau seems to be problematic since it is a three-dimensional and complicated structure.

Changes in cerebral perfusion occur in subarachnoid hemorrhage that possibly relate to clinical presentation and complications.

To evaluate changes in computed tomography perfusion (CTP) parameters between the acute and subacute stage of subarachnoid hemorrhage. To analyze correlation of these parameters to SAH severity and delayed cerebral ischemia.

Cerebral CT perfusion was assessed in a prospective cohort of 44 patients with acute subarachnoid hemorrhage at < 72 h (CTP1) and 8–10 days (CTP2), using the mean of all regions of interest. Regions of interest were located at arterial territories of the anterior, middle, and posterior cerebral artery and basal ganglia and midpons cerebellar hemispheres. Linear regression models (univariable and multivariable) were used to explore the association between changes in perfusion parameters (absolute and relative differences) and relevant clinical data.

Worse perfusion parameters on the first 72 h were correlated with poor admission clinical scores: cerebral blood flow positively correlated with Glasgow Coma Scale (r_S = 0.398, P = 0.008), and negatively correlated with Hunt & Hess scale (r_S = −0.348, P = 0.020) and World Federation of Neurosurgeons scale (r_S = −0.384, P = 0.010). Cerebral blood volume positively correlated with Glasgow Coma Scale (r_S = 0.332, P = 0.028) and negatively correlated with World Federation of Neurosurgeons scale (r_S = −0.353, P = 0.019). Mean transit time negatively correlated with Glasgow Coma Scale (r_S = −0.415, P = 0.005) and positively correlated with Hunt & Hess scale (r_S = 0.471, P = 0.001) and World Federation of Neurosurgeons scale (r_S = 0.386, P = 0.010) scores. There were no differences between absolute CTP1/CTP2 parameters. Patients with delayed cerebral ischemia had ΔTmax mean decrease of 2.08 s (95% CI = −4.04–−0.12; P = 0.038).

Early cerebral hypoperfusion correlates with poor clinical grade at admission in subarachnoid hemorrhage and with higher amounts of blood. Tmax was decreased at 8–10 days, in patients with delayed cerebral ischemia, which may favor the application value of Tmax in signaling delayed cerebral ischemia.

The embryological relationship between cerebellar arteries originating directly from the cavernous segment of the internal carotid artery and persistent trigeminal artery is not well understood.

To evaluate the incidence and pattern of cerebellar arteries originating from the internal carotid artery and persistent trigeminal artery, and to discuss their probable embryological relationship.

We reviewed 5113 angiographic studies from 5093 patients at our institution over the last eight years, searching for patients with persistent trigeminal artery and cerebellar arteries originating from a cavernous segment of internal carotid artery (persistent trigeminal artery variant).

Of the 5093 patients, 27 patients had persistent trigeminal artery or persistent trigeminal artery variant (0.53%). Twenty patients (6 men, 14 women; median age = 54 years) had persistent trigeminal artery (0.39%). Seven patients (2 men, 5 women, age range = 37–72 years; median age = 57 years) had a persistent trigeminal artery variant with persistent trigeminal artery terminating in a cerebellar artery without direct connection to the basilar artery (persistent trigeminal artery variant; 0.14%). The terminal branch of the persistent trigeminal artery variant was an anterior inferior carotid artery in five patients and a superior cerebellar artery in two patients. Of the seven patients having persistent trigeminal artery variant, four patients had another artery from the basilar artery to the anterior inferior carotid artery territory. In 6/20 patients with persistent trigeminal artery, there was an anterior inferior carotid artery arising from the persistent trigeminal artery. One of these patients showed another arterial branch from the basilar artery to the anterior inferior carotid artery territory.

Persistent trigeminal artery variant and cerebellar arteries originating from the persistent trigeminal artery are both believed to be a spectrum of incomplete fusion of the longitudinal neural arteries. Understanding the precise anatomy is important in diagnostic and therapeutic settings for related vascular disease.

We know little about the pathogenesis and diagnosis of retinal detachment.

To assess spontaneous changes in the cerebral cortex of patients with retinal detachment using voxel-based morphometry and to explore the relationship between retinal detachment and clinical behavioral performance.

Patients (14 men, 6 women; average age = 49.15 ± 10.32 years) with rhegmatogenous retinal detachment (duration of 24.05 ± 19.61 days) and 20 matched healthy controls were recruited. All participants underwent repeated functional magnetic resonance imaging scans. The original three-dimensional T1 brain images were analyzed using voxel-based morphometry and whole brain white matter volume and whole brain gray matter volume were compared with those of the control group. A receiver operating characteristic (ROC) curve was used to classify the mean gray matter volume values of the patients with retinal detachment compared with the controls.

Compared with the controls, whole brain gray matter volume was significantly reduced in patients with retinal detachment, as evidenced by changes in the right inferior frontal gyrus, right superior temporal gyrus, right anterior cingulate gyrus, and right cuneus. In addition, the posterior lobe of the cerebellum, left hippocampus, left cingulate gyrus, and left middle temporal gyrus were also obviously atrophied. Furthermore, whole brain white matter volume of the patients with retinal detachment showed a slight reduction. The ROC curve analysis of each brain region showed that the accuracy of the area under the curve was high.

We proved that patients with retinal detachment had unusual changes in the gray matter volume and white matter volume in vision-related brain regions, which could reveal potential pathological mechanisms of retinal detachment.

Recurrent high-grade gliomas progressing after surgery and temozolomide plus radiation therapy have traditionally been treated using antiangiogenic drugs as the first-line therapy. Since the phase 3 EORTC 26101 trial showed no significant benefit of administering antiangiogenic drugs, the need to identify a biomarker to classify subgroups of potential responders has increased.

To investigate the feasibility of using apparent diffusion coefficient as a predictor of the response of recurrent high-grade gliomas to bevacizumab or classifier for patients showing better response.

This retrospective study analyzed magnetic resonance images obtained from 39 patients at the time of high-grade glioma progression who were treated using bevacizumab. The apparent diffusion coefficient maps were quantified and modelled as a mixture of Gaussian functions. The correlation of their descriptors and the time to second progression was studied. Log-rank tests were performed to determine the power of these descriptors as the classifiers for patients exhibiting better survival.

None of the descriptors showed correlation with time to second progression (r < 0.35) but several of them stratified subgroups showing a better time to second progression passing log-rank tests (P < 0.02).

Apparent diffusion coefficient cannot be used to predict the time to second progression of recurrent high-grade gliomas treated with bevacizumab, but it can stratify groups with better time to second progression distributions.

Several neuroimaging studies demonstrated that visual deprivation led to significant cross-modal plasticity in the brain’s functional and anatomical architecture.

To investigate the pattern of the interhemispheric functional connectivity in individuals with late blindness using the voxel-mirrored homotopic connectivity (VMHC) and seed-based functional connectivity (FC) methods.

Forty-four individuals with late blindness (22 men, 22 women; mean age = 39.88 ± 12.84 years) and 55 sighted control individuals (35 men, 20 women; mean age = 43.13 ± 13.98 years)—closely matched for age, sex, and education—underwent resting-state magnetic resonance imaging scans. The VMHC and seed-based FC methods were applied to assess interhemispheric coordination in a voxel-wise manner.

Compared with the sighted control groups, the late blindness groups showed decreased VMHC values in the bilateral cuneus/calcarine/lingual gyrus (CUN/CAL/LING) (BA 17/18/19) (voxel level: P < 0.001, Gaussian random field [GRF] correction, cluster level: P < 0.005). Meanwhile, for seed-based FC analysis, compared with the sighted control group, the late blindness group showed a decreased FC between the right lower VMHC regions and the bilateral CUN/LING/CAL/precuneus (PreCUN)/left middle occipital gyrus (MOG) (BA 18/19/30/31) and left precentral gyrus (PreCG) and postcentral gyrus (PostCG) (BA 2/3/4/6). The late blindness group showed a decreased FC between the left lower VMHC regions and the bilateral CUN/LING/CAL/PreCUN (BA 18/19/31) and left PreCG and PostCG (BA 2/3/4/6) relative to the sighted control group (voxel level: P < 0.001, GRF correction, cluster level: P < 0.005). Moreover, a negative correlation was observed between the duration of blindness and VMHC values in the bilateral CUN/CAL/LING (r = −0.393, P = 0.008) in individuals with late blindness.

Our results indicated that late blindness induced substantial impairment of interhemispheric coordination in the visual cortex. This might reflect impaired visual fusion, visual recognition function, and top-down modulations in individuals with late blindness.

Measurement of iodine concentration from dual-energy or spectral computed tomography (CT) provides useful diagnostic information especially in patients suffering from malignant tumors of various origins.

The purpose of this study was to systematically investigate the accuracy of the measurement of iodine concentration, focusing on potential influencing factors and assessing its suitability for routine clinical use.

First, a 3D-printed cylindrical phantom was used to assess reliability of dual-energy CT-based iodine concentration measurement. Second, a semi-anthropomorphic phantom was used to evaluate the potential impact of positional variation of the target volume as typically seen in clinical scans. Finally, a reference vial was placed on the body surface of 38 patients undergoing abdominal dual-energy CT to analyze correlations between applied doses and patient diameters.

The position of the target volume within the cylindrical phantom and the applied dose level significantly influenced the magnitude of measured iodine concentrations (P < 0.001). We also found a significant difference in accuracy depending on target volume position in the semi-anthropomorphic phantom (P = 0.028). In patient scans, we observed an error of 19.6 ± 5.6% in iodine concentration measurements of a reference and significant, moderate to strong, negative correlations between measured iodine concentration, maximum patient diameter, and applied dose (maximum sagittal diameter: r = −0.455, P = 0.004; maximum coronal diameter: r=−0.517, P = 0.001; CTDI_vol: r = −0.385, P = 0.017)

Dual-energy CT-based iodine concentration measurement should be interpreted with caution. In clinical examinations, placement of a reference vial could be a potential solution to relativize errors.