Intravenous Contrast Administration Research Articles

Evaluation of Inflammatory Disease Activity in the Sacroiliac Joints Using Magnetic Resonance Imaging: A Comparative Analysis of Short-Tau Inversion Recovery, Post-Contrast, and Diffusion-Weighted Imaging –Preliminary Study

Introduction: It is essential to detect sacroiliitis earlier to decrease morbidity and unwanted complications such as ankylosing of sacroiliac joints. In recent studies, magnetic resonance imaging (MRI) serves as a key diagnostic tool for identifying sacroiliitis and is now included in the diagnostic criteria. We aim to detect the utility of diffusion-weighted imaging on the MRI in diagnosing sacroiliitis and measure ADC values for the response to treatment in future studies. Materials -methods: There were 39 patients (16 male, 20 female). A 1.5 Tesla MR device with a pelvic coil was used. The sequences were T1 (before and after intravenous contrast administration of gadolinium), T2-weighted fast field echo, short tau inversion recovery (STIR), diffusion-weighted (DW) images, and apparent diffusion coefficient (ADC) mapping. Sacroiliac joints were divided into four quadrants, and two radiologists interpreted all the sequences by giving scores from 0 to 3 depending on bone marrow edema from none to severe. The concordance of scores assigned to STIR, T1-weighted gadolinium-enhanced images, ADC mapping, and diffusion-weighted MR images was evaluated by calculating intraclass correlation coefficients. Results: A statistically significant positive correlation was observed between the activity scores derived from short tau inversion recovery (STIR) and other magnetic resonance (MR) sequences, namely T1-weighted gadolinium-enhanced images, apparent diffusion coefficient (ADC) mapping, and diffusion-weighted MR images. Conclusion: Active bone marrow abnormalities were identified with comparable efficacy using STIR imaging and other MR sequences (T1W-Gad, ADC mapping, DW-MR). In our study, we tried to emphasize the role of the diffusion-weighted images near the other sequences. Diffusion is a fast, easy-applied sequence. After increased experience in the diffusion-weighted images, routine application of this sequence will increase, and even becoming one of the diagnostic criteria will be inevitable. The difference in DWI from the other sequences is that it is measurable. The response to treatment may be followed up by ADC values.

Exploring bone density analysis on routine CT scans as a tool for opportunistic osteoporosis screening

The primary aim of this study was to evaluate computed tomography (CT)-based bone density analysis at the level of thoracic vertebra 12 (Th12) as a screening method for decreased bone density in patients admitted to the intensive care unit (ICU). Interobserver variability was analyzed. Secondary aims were to assess the prevalence of CT-based low bone density upon ICU admission in a cohort of COVID-19 patients and to assess the potential effect of long-term ICU stay on bone density in these patients. Retrospective single-center cohort study. ICU of the Leiden University Medical Center (LUMC), the Netherlands. Patients admitted to the ICU of the LUMC between March 1st, 2020 and February 1st, 2022 with a diagnosis of COVID-19, and a length of ICU stay of ≥ 21 days. In the included patients both baseline chest CT scans (obtained upon ICU admission) and follow-up chest CT scans (obtained ≥ 21 days after ICU admission) were available for analysis. A total of 118 CT scans in 38 patients were analyzed. There was a good interobserver variability, with an overall mean absolute difference (between measurements of three observers) of 9.7 Hounsfield Units (HU) and an intraclass correlation coefficient (ICC) of 0.93 (95% CI 0.88–0.96). The effect of intravenous contrast administration on bone density measurements was small (+ 7.5 HU (95% CI 3.4–11.5 HU)) higher in contrast enhanced CT images compared to non contrast enhanced CT images). Thirty-seven percent of patients had a bone density < 140 HU, suggestive of osteoporosis. No significant difference was found between bone density upon ICU admission and bone density at follow-up (≥ 21 days after ICU admission). Vertebral CT-based bone density analysis using routine CT scans is an easily applicable method to identify ICU patients with decreased bone density, which could enable enrollment in osteoporosis prevention programs. A high prevalence of low bone density was found in our cohort of ICU patients. There were no changes observed in bone density between baseline and follow-up measurements.

Differential Incidence of Contrast-Associated Acute Kidney Injury: Comparing Intravenous and Intraarterial Contrast Administration.

Contrast-associated acute kidney injury (CA-AKI) remains a significant concern in diagnostic and invasive procedures, particularly in the context of iodinated contrast material administration. The traditional definition of CA-AKI, based on serum creatinine elevation following contrast exposure, may not accurately capture its multifactorial nature. Studies have provided new insights into the differential incidence of CA-AKI between intravenous and intraarterial contrast administration, emphasizing the importance of tailored preventative strategies for high-risk procedures. This higher risk may arise from two proposed mechanisms: one implicating free radical formation leading to cytotoxicity and apoptosis in renal cells and another suggesting that contrast media alter renal hemodynamics, particularly in the outer medulla, by constricting the vasa recta and reducing medullary flow. Advances in technology and patient care, including contemporary use of low-osmolar contrast agents and hydration protocols, mitigate CA-AKI risk. Diagnostic and invasive procedures should not be avoided solely due to concerns about renal dysfunction if the patient is likely to benefit clinically.

#1829 Intravenous contrast exposure in stable CKD 4 and 5 patients and adverse renal outcomes: a propensity-score matched study

Abstract Background and Aims Previous studies of intravenous (IV) contrast administration in patients with CKD have focused on the association between contrast exposure and AKI. Here we explore the association of IV contrast administration for CT imaging with a broader range of adverse renal outcomes in patients with advanced CKD (stages 4 and 5). Method Data covering nephrology care in the West of Scotland were obtained from the Strathclyde Electronic Renal Patient Record. We included adult patients with an incident CT scan and an eGFR &amp;lt; 30 mL/min/1.73 m2 between April 2008 and May 2020. Patients with AKI were excluded. Structured query language (SQL) was used to analyse CT scan reports and identify whether IV contrast had been administered or not. Patient demographics (age, sex, Scottish index of multiple deprivation), co-morbidities, laboratory tests (including eGFR slope for 6 months preceding the study calculated by linear regression, eGFR at time of CT, C-reactive protein, urine protein:creatinine ratio), anthropometric measurements (blood pressure, body mass index), and medications were collected. The primary outcome was a composite renal outcome (AKI, sustained eGFR drop, renal replacement therapy [RRT], and renal death). Secondary outcomes included individual components of the composite outcome and all-cause death. AKI was defined as a 25% creatinine rise from index creatinine between days 7 and 14 post CT. Sustained eGFR drop was defined as two consecutive eGFR &amp;lt; 15 mL/min/1.73 m2 more than 4 weeks apart. Renal death was defined as death from acute kidney injury, chronic kidney disease or end stage renal disease without dialysis. A propensity-score matched dataset was created using a 1:2 ratio with no replacement. Multivariable logistic, proportional hazards and Fine-Gray (competing risks) regressions were used to identify independent correlates of the primary and secondary outcomes. Missing data were multiply imputed using the “mice: Multivariate Imputation by Chained Equations” package on R studio. Results 9226 patients with an eGFR &amp;lt; 30 mL/min/1.73 m2 underwent an incident CT scan during the study period. Among 6371 patients meeting the inclusion criteria (3067 (48.1%) men; mean [SD] age 72.8 [13.8] years; mean [SD] eGFR 20.4 [6.9] ml/min/1.73 m2), 875 had received IV contrast. A propensity-score matched dataset was generated consisting of 875 patients who had a contrast CT and 1750 patients with non-contrast CT. On multivariable analysis, contrast administration was associated with a higher risk of AKI (HR 1.49, 95% CI 1.06-2.10, p = 0.02) but not with the composite renal outcome (HR 0.89, 95% CI 0.66-1.20, p = 0.45). Contrast administration did not change the risk of a sustained eGFR drop (HR 0.88, 95% CI 0.54-1.43, p = 0.60), RRT (HR 0.85, 95% CI 0.61-1.20, p = 0.36), or all-cause death (HR 0.95, 95% CI 0.76-1.19, p = 0.65). We did not identify an effect of contrast administration on the time to composite renal outcome, RRT, or all-cause death by Cox regression (HR 0.92, 95% CI 0.70-1.22, p = 0.56; HR 0.88, 95% CI 0.64-1.23, p = 0.46; and HR 1.07, 95% CI 0.94-1.20, p = 0.30, respectively). On Fine-Gray regression, we did not identify an impact of contrast administration on the risk of RRT (HR 0.84, 95% CI 0.63-1.12, p = 0.24) or death (HR 1.07, 95% CI 0.95-1.20, p = 0.27). In subgroup analysis in patients with an index eGFR &amp;lt; 20 mL/min/1.73 m2, contrast administration was not associated with the composite renal outcome (HR 0.79, 95% CI 0.51-1.22, p = 0.28), RRT (HR 0.85, 95% CI 0.52-1.39, p = 0.51), AKI (HR 1.28, 95% CI 0.66-2.45, p = 0.46), or death (HR 0.94, 95% CI 0.64-1.39, p = 0.76). Conclusion In a stable population with advanced CKD, we identified an association between IV contrast administration and the risk of AKI, but this did not translate in adverse long-term renal outcomes. These findings suggest that increases in serum creatinine post-IV contrast in patients with stable CKD are not clinically significant.

Should the presence of chronic kidney disease preclude intravenous contrast administration when considering computed tomography imaging?

Should the presence of chronic kidney disease preclude intravenous contrast administration when considering computed tomography imaging?

Intravenous administration of ultrasound contrast to critically ill pediatric patients.

The off-label use of contrast-enhanced ultrasound has been increasingly used for pediatric patients. The purpose of this retrospective study is to report any observed clinical changes associated with the intravenous (IV) administration of ultrasound contrast to critically ill neonates, infants, children, and adolescents. All critically ill patients who had 1 or more contrast-enhanced ultrasound scans while being closely monitored in the neonatal, pediatric, or pediatric cardiac intensive care units were identified. Subjective and objective data concerning cardiopulmonary, neurological, and hemodynamic monitoring were extracted from the patient's electronic medical records. Vital signs and laboratory values before, during, and after administration of ultrasound contrast were obtained. Statistical analyses were performed using JMP Pro, version 15. Results were accepted as statistically significant for P-value<0.05. Forty-seven contrast-enhanced ultrasound scans were performed on 38 critically ill patients, 2 days to 17 years old, 19 of which were female (50%), and 19 had history of prematurity (50%). At the time of the contrast-enhanced ultrasound scans, 15 patients had cardiac shunts or a patent ductus arteriosus, 25 had respiratory failure requiring invasive mechanical oxygenation and ventilation, 19 were hemodynamically unstable requiring continual vasoactive infusions, and 8 were receiving inhaled nitric oxide. In all cases, no significant respiratory, neurologic, cardiac, perfusion, or vital sign changes associated with IV ultrasound contrast were identified. This study did not retrospectively identify any adverse clinical effects associated with the IV administration of ultrasound contrast to critically ill neonates, infants, children, and adolescents.

Assessing the necessity of intravenous contrast for computed tomography in the acute undifferentiated abdomen.

Undifferentiated abdominal pain in the emergency setting is frequently investigated with an intravenous contrast enhanced CT as a first line diagnostic test. However, global contrast shortages restricted the use of contrast for a period in 2022, altering standard practice with many scans performed without intravenous contrast. Whilst IV contrast can be useful to assist with interpretation, its necessity in the setting of acute undifferentiated abdominal pain is not well described, and its use comes with its own risks. This study aimed to assess the shortcomings of omitting IV contrast in an emergency setting, by comparing the rate of CT scans with "indeterminate" findings with and without the use of IV contrast. Data from presentations to a single centre emergency department for undifferentiated abdominal pain prior to and during contrast shortages in June 2022 were retrospectively compared. The primary outcome was the rate of diagnostic uncertainty, where the presence or absence of intra-abdominal pathology could not be ascertained. 12/85 (14.1%) of the unenhanced abdominal CT scans provided an uncertain result, compared with 14/101 (13.9%) of control cases performed with intravenous contrast (P = 0.96). There were also similar rates of positive and negative findings between the groups. Omitting intravenous contrast for abdominal CT in the setting of undifferentiated abdominal pain demonstrated no significant difference in the rate of diagnostic uncertainty. There are significant potential patient, fiscal and societal benefits as well as potential improvements to emergency department efficiency with the reduction of unnecessary intravenous contrast administration.

Unusual Progressive Hepatic Echogenicity of the Pediatric Liver Following Intravenous Sonographic Contrast Administration

Contrast-enhanced ultrasound is a valuable tool to evaluate liver lesions in a pediatric patient cohort. Unusual progressive hepatic echogenicity (UPHE) is a self-limiting phenomenon noted in a cohort of children after administration of ultrasonographic contrast agents (UCAs). UPHE appears initially as heterogeneous branching similar to portal venous gas, culminating in a diffuse globular appearance. The etiology of UPHE is unclear and may be from underlying hepatic microvascular disease or altered gut permeability. This case series describes pediatric patients with UPHE following UCA bolus and discusses its potential mechanisms in children.

Brain tumour segmentation with incomplete imaging data.

Progress in neuro-oncology is increasingly recognized to be obstructed by the marked heterogeneity-genetic, pathological, and clinical-of brain tumours. If the treatment susceptibilities and outcomes of individual patients differ widely, determined by the interactions of many multimodal characteristics, then large-scale, fully-inclusive, richly phenotyped data-including imaging-will be needed to predict them at the individual level. Such data can realistically be acquired only in the routine clinical stream, where its quality is inevitably degraded by the constraints of real-world clinical care. Although contemporary machine learning could theoretically provide a solution to this task, especially in the domain of imaging, its ability to cope with realistic, incomplete, low-quality data is yet to be determined. In the largest and most comprehensive study of its kind, applying state-of-the-art brain tumour segmentation models to large scale, multi-site MRI data of 1251 individuals, here we quantify the comparative fidelity of automated segmentation models drawn from MR data replicating the various levels of completeness observed in real life. We demonstrate that models trained on incomplete data can segment lesions very well, often equivalently to those trained on the full completement of images, exhibiting Dice coefficients of 0.907 (single sequence) to 0.945 (complete set) for whole tumours and 0.701 (single sequence) to 0.891 (complete set) for component tissue types. This finding opens the door both to the application of segmentation models to large-scale historical data, for the purpose of building treatment and outcome predictive models, and their application to real-world clinical care. We further ascertain that segmentation models can accurately detect enhancing tumour in the absence of contrast-enhancing imaging, quantifying the burden of enhancing tumour with an R 2 > 0.97, varying negligibly with lesion morphology. Such models can quantify enhancing tumour without the administration of intravenous contrast, inviting a revision of the notion of tumour enhancement if the same information can be extracted without contrast-enhanced imaging. Our analysis includes validation on a heterogeneous, real-world 50 patient sample of brain tumour imaging acquired over the last 15 years at our tertiary centre, demonstrating maintained accuracy even on non-isotropic MRI acquisitions, or even on complex post-operative imaging with tumour recurrence. This work substantially extends the translational opportunity for quantitative analysis to clinical situations where the full complement of sequences is not available and potentially enables the characterization of contrast-enhanced regions where contrast administration is infeasible or undesirable.

Abstract WMP60: Eliminating False Positive Detections Of Intracranial Hemorrhage (ICH) Using RAPID ICH 3

Introduction: Prompt detection of intracranial hemorrhage (ICH) on a non-contrast head CT (NCCT) is critical to initial patient triage. Several ICH detection and notification programs now exist, but none presently generate locations or segmentations of suspected ICH, and false-positive notifications are not easily identified. We investigated an enhanced ICH detection tool with heightened immunity to false-positive diagnosis. Methods: NCCT scans from 3 large databases were evaluated for the presence of an ICH (IPH, IVH, SAH or SDH) of &gt;0.4 ml by the automated RAPID ICH 3.0 software module and compared to a consensus detection from 3 neuroradiology experts. Scans were excluded for (1) severe CT acquisition artifacts, (2) prior neurosurgical procedures or (3) intravenous contrast administration. ICH detection accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and positive and negative likelihood ratios by RAPID ICH 3 were determined. Results: A total of 790 studies were included. RAPID ICH 3.0 correctly identified 399/411 ICH-positive cases and 378/379 ICH-negative cases, resulting in a sensitivity of 98.08% and specificity 99.74%, positive predictive value 99.75%, and negative predictive value 96.92% for ICH detection. The positive and negative likelihood ratios for ICH detection were similarly favorable at 367.93 and 0.03 respectively. Mean processing time was &lt;40 seconds. Conclusions: In this large data set of nearly 800 patients, the RAPID ICH 3.0 automated software maintained a high sensitivity for detection of ICH, while essentially eliminating false positive identifications, leading to very high positive predictive value.

Renal outcomes following intravenous contrast administration in patients with acute kidney injury: a multi-site retrospective propensity-adjusted analysis.

Evidence of an association between intravenous contrast media (CM) and persistent renal dysfunction is lacking for patients with pre-existing acute kidney injury (AKI). This study was designed to determine the association between intravenous CM administration and persistent AKI in patients with pre-existing AKI. A retrospective propensity-weighted and entropy-balanced observational cohort analysis of consecutive hospitalized patients ≥ 18years old meeting Kidney Disease Improving Global Outcomes (KDIGO) creatinine-based criteria for AKI at time of arrival to one of three emergency departments between 7/1/2017 and 6/30/2021 who did or did not receive intravenous CM. Outcomes included persistent AKI at hospital discharge and initiation of dialysis within 180days of index encounter. Our analysis included 14,449 patient encounters, with 12.8% admitted to the intensive care unit (ICU). CM was administered in 18.4% of all encounters. AKI resolved prior to hospital discharge for 69.1%. No association between intravenous CM administration and persistent AKI was observed after unadjusted multivariable logistic regression modeling (OR 1; 95% CI 0.89-1.11), propensity weighting (OR 0.93; 95% CI 0.83-1.05), and entropy balancing (OR 0.94; 95% CI 0.83-1.05). Sub-group analysis in those admitted to the ICU yielded similar results. Initiation of dialysis within 180days was observed in 5.4% of the cohort. An association between CM administration and increased risk of dialysis within 180days was not observed. Among patients with pre-existing AKI, contrast administration was not associated with either persistent AKI at hospital discharge or initiation of dialysis within 180days. Current consensus recommendations for use of intravenous CM in patients with stable renal disease may also be applied to patients with pre-existing AKI.

Urogenital fistula associated with complex dystocia and emergency ovariohysterectomy in a juvenile dog

AbstractA 1‐year‐old, female, spayed dog was referred for urinary incontinence, first noted after a complex dystocia and caesarean section with ovariohysterectomy. Transabdominal ultrasonography and computed tomography with intravenous contrast administration revealed a fluid‐filled tubular structure caudodorsal to the urinary bladder. Routine cystourethroscopy was unremarkable. A retrograde cystourethrogram revealed a 15 mm long connection between the urethra and a structure presumed to be a uterine body remnant. During exploratory laparotomy, the uterine remnant and urethra were separated, leaving oval defects approximately 15 mm long in both; these were then closed. A urinary catheter was left in place for 6 days. A urethrogram performed during catheter removal confirmed closure of the fistula, and the dog was subsequently continent. To the authors’ knowledge, this is the first description of a urogenital fistula suspected to be associated with dystocia and emergency ovariohysterectomy in a dog.

Diagnostic power of vertebral hydroxyapatite concentration measurements in spectral CT for osteoporosis-associated fractures and impact of intravenous contrast administration.

To evaluate the diagnostic power of using vertebral hydroxyapatite concentration measurements in unenhanced and contrast-enhanced spectral CT for detecting and predicting the risk of osteoporosis-associated fractures. L1 of 210 patients (105 men, 105 women; mean age, 64 years, range, 19-103 years) who had undergone spectral CT examinations from January 1, 2018, to March 1, 2019, were retrospectively analyzed. Patient data for 3 years after spectral CT were retrieved from electronic medical record information systems to obtain the incidence of osteoporotic fractures. Baseline vertebral cancellous hydroxyapatite concentration from unenhanced and contrast-enhanced late-arterial-phase images was measured. The receiver operating characteristic curves were used to evaluate the diagnostic power for detecting and predicting the 3-year risk of osteoporosis-associated fractures using hydroxyapatite concentrations in both phases. The hydroxyapatite concentrations in both phases had good diagnostic power to detect fractures at baseline. The sensitivity and specificity for predicting one or more osteoporosis-associated fractures within 3 years after spectral CT were 76.80% and 93.10%, respectively, using the cutoff of 74.79 mg/cm3 in vertebral hydroxyapatite concentration in the unenhanced CT phase, and 82.87% and 82.76%, respectively, using the cutoff of 84.65 mg/cm3 in the late-arterial phase. Furthermore, there was no significant difference in the diagnosis between unenhanced and enhanced CT-derived hydroxyapatite concentrations (p = 0.360). Both unenhanced and enhanced spectral CT-derived hydroxyapatite concentrations can accurately detect and predict future risk of osteoporosis-associated fractures. The hydroxyapatite concentration assessed in the late-arterial phase may have a similar diagnostic efficacy to that in the unenhanced phase. • A cutoff of 74.79 mg/cm3 of vertebral hydroxyapatite concentration in the unenhanced CT scans had 76.80% sensitivity and 93.10% specificity to predict one or more osteoporosis-associated fractures within 3 years after spectral CT examinations. • A cutoff of 84.65 mg/cm3 of vertebral hydroxyapatite concentration in the late-arterial-enhanced CT scans had 82.87% sensitivity and 82.76% specificity to predict one or more osteoporosis-associated fractures within 3 years after spectral CT examinations. • The hydroxyapatite concentration assessed in the late-arterial phase may have a similar diagnostic efficacy to that in the unenhanced phase.

Clinics in diagnostic imaging (216).

Clinics in diagnostic imaging (216).

Patient perspectives on repeated contrast-enhanced mammography and magnetic resonance during neoadjuvant chemotherapy of breast cancer.

The burden perceived by the patient of repeated imaging required for neoadjuvant chemotherapy (NAC) monitoring warrants attention due to the increased use of NAC and imaging. To evaluate and compare the experienced burden associated with repeated contrast-enhanced mammography (CEM) and magnetic resonance imaging (MRI) during NAC for breast cancer from the patient perspective. Approval from the ethics committee and written informed consent were obtained. In this prospective study, CEM and MRI were performed on 38 patients with breast cancer before, during, and after NAC in a tertiary cancer center. The experienced burden was evaluated with a self-reported questionnaire addressing duration, comfort, anxiety, positioning, and intravenous contrast administration, each measured on a 5-point Likert scale. The participants were asked their preference between CEM or MRI. Statistical comparisons were performed and P<0.05 was considered significant. Most participants (n = 29, 76%) preferred CEM over MRI (P = 0.0008). CEM was associated with a significantly shorter duration (P < 0.001), greater overall comfort (P < 0.01), more comfortable positioning (P = 0.01), and lower anxiety (P = 0.03). Intravenous contrast administration perception revealed no significant difference. Only 4 (10%) participants preferred MRI over CEM, due to the absence of breast compression. In the hypothetical scenario of equal diagnostic accuracy, most participants preferred CEM and compared CEM favorably to MRI in all investigated features at repeated imaging required for NAC response assessment. Our results indicate that repeated examinations with CEM is well tolerated and constitutes a patient-friendly alternative for NAC imaging monitoring in breast cancer.

CT after interhospital transfer in acute ischemic stroke: Imaging findings and impact of prior intravenous contrast administration.

Large vessel occlusion (LVO) stroke patients routinely undergo interhospital transfer to endovascular thrombectomy capable centers. Imaging is often repeated with residual intravenous (IV) iodine contrast at post-transfer assessment. We determined imaging findings and the impact of residual contrast on secondary imaging. Anterior circulation LVO stroke patients were selected out of a consecutive cohort. Directly admitted patients were contrast naïve, and transferred patients had previously received IV iodine contrast for stroke assessment at the referring hospital. Two independent readers rated the visibility of residual contrast on non-contrast computed tomography (CT) after transfer and assessed the hyperdense vessel sign. Multivariate linear regression analysis was used to investigate the association of the Alberta Stroke Program Early CT score (ASPECTS) with prior contrast administration, time from symptom onset (TFSO), and CTP ischemic core volume in both directly admitted and transferred patients. We included 161 patients, with 62 (39%) transferred and 99 (62%) directly admitted patients. Compared between these groups, transferred patients had a longer TFSO-to-imaging at our institution (median: 212 vs. 75 min, p < 0.001) and lower ASPECTS (median: 8 vs. 9, p < 0.001). Regression analysis presented an independent association of ASPECTS with prior contrast administration (β = -0.25, p = 0.004) but not with TFSO (β = -0.03, p = 0.65). Intergroup comparison between transferred and directly admitted patients pointed toward a stronger association between ASPECTS and CTP ischemic core volume in transferred patients (β = -0.39 vs. β = -0.58, p = 0.06). Detectability of the hyperdense vessel sign was substantially lower after transfer (66 vs. 10%, p < 0.001). Imaging alterations due to residual IV contrast are frequent in clinical practice and render the hyperdense vessel sign largely indetectable. Larger studies are needed to clarify the influence on the association between ASPECTS and ischemic core.

A comparative study of different contrast administration routes efficiency performed on in vivo colorectal cancer models

Purpose of the study. The investigation is aimed to provide a systematic comparison of different contrasting methods for in vivo micro-CT diagnostic of orthotopic colorectal cancer models extracted by ortotopic implantation into the caecum of immunocompromised mice BALB/c Nude lines.Materials and methods. BALB/c Nude (N = 25) female mice were implanted by transplanted human colorectal cancer strain into the cecum. 20 days after the implantation mice were administered with iodine-based contrast agent Optiray by means of different administration method (intravenously, per os, intraperitoneally, per rectum) and micro-CT scans have been registered via Quantum GX2 tomograph. Measurement of tumor nodes was performed both by means of estimation from micro-CT images via RadiAnt DICOM Viewer software and by means of explicit measurements using calipers upon laparotomy and posthumously. At the last stage of the study, the animals were euthanized by cervical dislocation. The tumors were excised, measured with a caliper and placed in 10 % formalin for the standard histological analysis according to the standard methods.Results. The average volumes of tumor xenografts in animals with intravenous, oral, and intraperitoneal contrast administration measured at micro-CT were 53.7 ± 5.2 mm3, 52.7 ± 6.4 mm3 and 63.6 ± 5.6 mm3 respectively; measured at laparotomy – 43.0 ± 5.5 mm3, 44.5 ± 5.4 mm3 and 58.5 ± 5.5 mm3 respectively; measured post-mortem – 55.2 ± 6.6 mm3, 53.2 ± 8.8 mm3 and 65.9 ± 3.8 mm3 respectively. The average volumes of tumor xenografts isolated post-mortem in these groups were comparable with the values shown at micro-CT, but larger than the volumes measured at laparotomy.Conclusion. The results obtained demonstrated that intravenous, peroral and intraperitoneal administration techniques provide the best visualization of laboratory rodents pathological tissue upon in vivo micro-CT diagnostics and thus are preferred.

Multidetector Computed Tomography Perfusion in Head and Neck Squamous Cell Carcinomas: Evaluation of a Dose Reduction Strategy.

Background Computed tomography perfusion (CTp), a useful technique in oncology, is not widely utilized due to the high radiation dose delivered from it. It involves scanning the region of interest every second for 50 seconds following intravenous contrast administration. Doubling sampling interval (SI) to 2 seconds will half the radiation dose, but may impact its effectiveness, which needs to be evaluated. Objectives To evaluate a dose reduction strategy in CTp by determining agreement between standard dose (SD) CTp (acquisition with SI 1 second) and low-dose CTp techniques with SI of 2 seconds (achieved either by reconstruction only or true low-dose acquisition). Materials and methods This cross-sectional study was conducted on histopathology-proven head and neck squamous cell carcinoma (HNSCC) patients who underwent CTp on 64 slice multidetector CT. A total of 56 patients had SD and 24 patients underwent true low dose (LD) acquisition. SD data were also reconstructed at SI 2 seconds to obtain a dataset simulating low dose (low-dose reconstruction [LDr]). Paired t -test was applied to compare CTp in SD and LDr groups and the Bland-Altman plot drawn to calculate 95% confidence limit of agreement. The Kolmogorov-Smirnov test compared CTp parameters for LDr and LD groups. Results There was no statistical difference in CTp parameters (except blood flow in malignant) in SD and LDr groups for both malignant and normal tissues. CTp of malignant tissue was not statistically different in LDr and LD groups but the radiation dose was half in the LD group. Conclusion Reduction of radiation dose to half achieved by doubling the SI does not affect the CTp parameters significantly. So LD acquisitions will increase the use of CTp in HNSCC.

Diagnostic Accuracy of Multislice CT Scan in the Detection of Cervical Lymph Node Metastasis in Head and Neck Cancers

Objectives: To determine the diagnostic accuracy of multislice CT scan in the detection of cervical lymph node metastasis in head and neck cancers, taking histopathology as gold standard. Study design: Descriptive, cross-sectional study. Settings: Department of Radiology, Jinnah Hospital, Lahore Study duration: 8th January 2018 to 7th July 2018 Materials &amp; Methods: Total 95patients with squamous cell carcinoma of head and neck, 15-55 years of age of both genders were selected. All the patients with prior radiation to head and neck, already proven histopathology, CRF and claustrophobic patients were excluded. Multislice computed tomography of neck was performed on Toshiba Aquilion Multislice CT scanner before and after intravenous contrast administration. Each multislice CT scan findings were looked for malignant cervical lymph nodes. Multislice CT scan findings were compared with histopathology findings. Results: Mean age was 43.21 ± 8.16 years. Out of these 95 patients, 54 (56.84%) were males and 41 (43.16%) were females with ratio of 1.3:1.All the patients were subjected to CT of neck and found that 48 were True Positive and 04 were False Positive. Among 43, CT negative patients, 04 (False Negative) had malignant cervical nodes on histopathology whereas 39 (True Negative) had benign cervical nodes on histopathology (p=0.0001). Overall sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of multislice CT scan in the detection of cervical lymph node metastasis in head and neck cancers, taking histopathology as gold standard was 92.31%, 90.70%, 92.31%, 90.70% and 91.58% respectively. Conclusion: This study concluded that multislice CT scan is a highly sensitive and accurate non-invasive modality for detecting cervical lymph node metastasis in head and neck cancers. Keywords: Head and Neck Cancers, Cervical Lymph Node Metastasis, Computed Tomography.

The potential effect of iopamidol contrast on renal function in patients infected with SARS-CoV-2 virus: A retrospective cohort study.

Many types of computed tomography (CT) scans require the use of contrast. Acute kidney injury (AKI) is a known adverse effect of intravenous contrast administration. To our knowledge, the effects of low-osmolar contrast agents such as iopamidol on renal function in patients infected with the SARS-CoV-2 virus have never been studied. This study investigates the incidence of AKI following iopamidol contrast administration in patients infected with the SARS-CoV-2 virus. This retrospective cohort study included two groups: patients who received CT pulmonary angiography who were infected with SARS-CoV-2 virus and those who tested negative for SARS-CoV-2. Data were collected from the electronic medical record of a single hospital from January 1, 2020, to September 15, 2020. AKI was defined using the Kidney Disease: Improving Global Outcomes definition: increase in serum creatinine by ≥0.3 mg/dL (≥26.5 mcmol/L) within 48 h, or increase in serum creatinine to ≥1.5 times baseline, which is known or presumed to have occurred within the prior 7 days, or urine volume <0.5 mL/kg/h for 6 h. AKI occurred in 13.51% of patients in the SARS-CoV-2 positive group and 16.92% of patients in the negative group. Using a two-sample test to compare the equality of proportions (with continuity correction factor), we found there is no significant difference in the two proportions (P = 0.3735). There was no significant difference in the incidence of AKI between SARS-CoV-2 positive and negative groups. Given the limitations of this study, further work must be done on this topic.