Replacing true unenhanced imaging in renal carcinoma with virtual unenhanced images in dual-energy spectral CT: a feasibility study

AIM

To investigate the clinical value of virtual unenhanced (VNC) spectral computed tomography (CT) images to replace the conventional true unenhanced spectral CT images (TNC) in diagnosing renal carcinoma.

MATERIALS AND METHODS

Fifty-six cases of renal carcinoma confirmed by histopathology underwent conventional plain CT and contrast-enhanced spectral CT at arterial phase (AP) and venous phase (VP). VNC images were generated on an AW4.6 workstation. The CT attenuation, image noise, contrast-to-noise ratio (CNR), and signal-noise-ratio (SNR) of the renal lesions and normal kidneys, long and short axis diameters of the lesion were measured from the three image sets and analysed using one-way analysis of variance (ANOVA). Two radiologists evaluated image quality subjectively using a five-point score, and lesion signature using a three-point score. Image quality scores were compared statistically and tested for consistency.

RESULTS

The two reviewers had good agreement for subjective evaluation (Kappa>0.70) and there was no difference in the quality of the scores among the three image groups. The lesion signature scores were all above the acceptable level. The CNR and SNR values in VNC were significantly higher than in TNC (p<0.05). VNC images had lower renal noise than in TNC (p<0.05). There was no difference in the long and short axis diameters of the lesion among the three image groups. VNC had higher CT attenuation values for the lesion and kidney than TNC (p<0.05), but the differences were <5 HU.

CONCLUSION

VNC images in spectral CT may be used to replace the conventional plain CT to reduce imaging duration and radiation dose in diagnosing renal carcinoma.

Prevalence of Coronary Artery Calcium in Patients With Atrial Fibrillation With and Without Cardiovascular Risk Factors

The burden of coronary artery atherosclerosis in patients with atrial fibrillation (AF) is unknown. We aimed to assess the coronary artery calcium (CAC) in AF patients. We retrospectively analyzed 324 consecutive patients with AF who had CT angiogram before AF ablation and their cardiovascular risk were prospectively collected. Mean age of the cohort was 66 years and 71% were male. The previous history of coronary artery disease (CAD) was present in 19% (n = 63) and CAC was positive in all. In patients without known CAD (n = 261), CAC was present in 70% (n = 182) with a comparable prevalence between men and women, which raised the prevalence of coronary atherosclerosis to 76% (n = 245) for the entire cohort. The median CAC score was 170 (range 1 to 6,157) and largely in multivessel distribution in patients without known CAD. Presence of CAC increased with an increasing number of cardiovascular risk factors. Nevertheless, CAC was present in 58% (n = 40) of patients without conventional cardiovascular risk factors. If CAC score >100 was considered as CAD equivalent as 10-year risk of incident atherosclerotic cardiovascular diseases is >7.5% it would have resulted in higher CAD prevalence of 52% and significant reclassification of CHA₂DS₂-VASc score in 41% of patients without known CAD. In conclusion, coronary calcium is highly prevalent in AF patients, including those without cardiovascular risk factors. Advanced CAC can potentially shift CHA₂DS₂-VASc score in many AF patients. Our findings suggest that characterizing CAC in AF may be clinically valuable in thromboembolic risk stratification and management of preventive cardiac therapies.

Activation of sulfite autoxidation with CuFe2O4 prepared by MOF-templated method for abatement of organic contaminants

Copper ferrite (denoted as CuFe₂O_4MOF), prepared via a complexation reaction to obtain bimetal-organic frameworks (Cu/Fe bi-MOFs), followed by a combustion process to remove the MOF template, is employed as a heterogeneous activator to promote sulfite autoxidation for the removal of organic contaminants. At pH 8.0, more than 80% of the recalcitrant organic contaminant iohexol (10 μM) can be removed within 2 min by the activation of sulfite (500 μM) with CuFe₂O_4MOF (0.1 g L^-1). CuFe₂O_4MOF exhibits more pronounced catalytic activity in accelerating sulfite autoxidation for iohexol abatement compared to that fabricated by hydrothermal and sol-gel combustion methods. Radical quenching studies suggest that the sulfate radical (SO₄^•-) is the main reactive species responsible for iohexol abatement. The performance of CuFe₂O_4MOF/sulfite for iohexol abatement can be affected by several critical influencing factors, including the solution pH and the presence of humic acid, Cl^-, and HCO₃^-. The effect of the ionic strength and the results of the attenuated total reflectance-Fourier transform infrared (ATR-FTIR) analysis indicate that sulfite autoxidation in the presence of CuFe₂O_4MOF involves an inner-sphere interaction with the surface Cu(II) sites of CuFe₂O_4MOF. X-ray photoelectron spectroscopy (XPS) characterization suggests that the surface Cu(II)-Cu(I)-Cu(II) redox cycle is responsible for efficient SO₄^•- production from sulfite. Overall, CuFe₂O_4MOF can be considered an alternative activator for sulfite autoxidation for potential application in the treatment of organic-contaminated water.

Fat-modified computed tomography severity index (CTSI) is a better predictor of severity and outcome in patients with acute pancreatitis compared with modified CTSI

BACKGROUND

The amount of intra-abdominal fat on CT correlates positively with the severity of acute pancreatitis (AP). The objective of the study was to evaluate a fat-modified CT severity index (FMCTSI) and compare its performance with MCTSI.

MATERIALS AND METHODS

For this retrospective study, 99 patients with AP who underwent contrast-enhanced CT between 3 and 7 days after pain onset were divided into a training cohort (n = 75) and a validation cohort (n = 24). MCTSI was calculated. The total adipose tissue (TAT), visceral adipose tissue (VAT), and total to visceral fat ratio (TVFR) were computed using semi-automatic software. These parameters were given a score of 1-3. FMCTSI was calculated by adding the fat score to MCTSI. Concordance for diagnosing the severity of AP was assessed. Areas under receiver operating characteristic curves (AUC) for predicting clinical outcomes were compared between FMCTSI and MCTSI. The diagnostic performance of the FMCTSI in the validation cohort was also evaluated.

RESULTS

In the training cohort, our proposed FMCTSI performed better than MCTSI for all the outcome parameters. The highest concordance for the severity of AP was achieved for VAT-MCTSI. For all outcome parameters, the highest AUC was seen for TVFR-MCTSI. In the validation cohort, the FMCTSI achieved diagnostic performance similar to the training cohort with the highest AUC for TVFR-MCTSI.

CONCLUSION

FMCTSI is a better CT index than MCTSI for predicting the severity and clinical outcomes of AP. Among the various FMCTSI parameters, TVFR-MCTSI is the best performer.

Application of multiple injections of contrast agent in head and neck CT arteriovenous angiography in children: Study protocol clinical trial (SPIRIT Compliant)

OBJECTIVE

To investigate the application value of multiple injections of contrast agent in head and neck CT arteriovenous angiography in children.

METHODS

A total of 100 children aged 6 to 7 years who needed head and neck CT arteriovenous angiography were prospectively selected. They were randomly divided into a control group and a research group, with 50 children in each group. The same scanning parameters and reconstruction methods were used. The right median cubital vein was injected intravenously with the contrast agent Omnipaque (350 mg I/ml). For children in the control group, a bolus of undiluted contrast agent (dose was 2 ml/kg, upper limit was 50 ml) was injected 1 time. The arterial phase and vein phase of the head and neck vessels were scanned. For children in the research group, a contrast agent bolus diluted with saline to a concentration of 20% was first injected (dose was 1 ml/kg, upper limit was 25 ml), and then an undiluted contrast agent bolus (dose was 1 ml/kg, upper limit was 25 ml) was injected. Thresholds were used to trigger the scanning of the head and neck arterial phases. The CT image quality of the head and neck arteries and veins, radiation dose and contrast agent dose were compared between the 2 groups.

RESULTS

Subjective evaluation of CT image quality of arteries: there were 47 cases of 4 points and 3 cases of 3 points in the control group and 34 cases of 4 points and 16 cases of 3 points in the research group. Subjective evaluation of CT image quality of veins: there were 47 cases of 4 points and 3 cases of 3 points in the control group and 5 cases of 4 points, 42 cases of 3 points and 3 cases of 2 points in the research group. The CT value of brain arterial vessel enhancement was higher in the control group than the research group, and the difference was statistically significant (P < .05). The CT value of vein enhancement was higher in the control group than the research group, and the difference was statistically significant (P < .05). The X-ray dose in the research group was 51% lower than that in the control group; the contrast agent dose in the research group was 44% lower than that in the control group.

CONCLUSION

For the head and neck enhanced CT examination of children, the method of first bolus injection of 20% diluted contrast agent and later bolus injection of undiluted contrast agent can clearly demonstrate the head and neck arteries and veins one time, reducing the X-ray dose and contrast agent dose, which has clinical practical value in the enhanced CT examination of children with head and neck disease.

Venous thrombosis and segmental hypoperfusion in amebic liver abscess: MDCT demonstration and its implications

PURPOSE

To report venous thrombosis and associated perfusion defect in amebic liver abscess (ALA) using MDCT.

METHOD

MDCT images of 62 patients with ALA were reviewed for venous thrombosis and associated perfusion abnormalities.

RESULT

The study found 43 (69%) patients with venous thrombosis: portal vein thrombosis (PVT) occurred in 39, hepatic vein thrombosis (HVT) in 37 and inferior vena cava (IVC) thrombosis in 4. Combined PVT and HVT occurred in 33 (77%) patients. The portal vein thrombi remained localized in subsegmental branches in 25 patients and extended to segmental branches in 14. The hepatic vein thrombi were confined to peripheral branches in 18 patients; they progressed to the main trunk in 19 and to the IVC in 4. A wedge-shaped hypoattenuating zone suggesting ischemia was identified in 33 (77%) patients in portal phase: 31 had combined PVT and HVT, 2 had HVT alone, but none had PVT alone. It occurred significantly more often with combined PVT and HVT than HVT alone (p = 0.05). Arterial phase enhancement occurred in 2 of 13 patients with multiphasic CT. All patients were symptomatic despite medical therapy and therefore required percutaneous drainage. About half of the patients were identified with ruptured abscesses. Segmental atrophy was observed in seven of nine patients who underwent follow-up CT.

CONCLUSION

Combined PVT and HVT commonly occur with ALA and often manifests as segmental hypoperfusion in portal venous phase, indicating ischemia. The detection of such events by CT may be indicative of severe disease that requires aggressive management involving percutaneous drainage.

Application of low-concentration contrast agents and low-tube-voltage computed tomography to chest enhancement examinations: A multicenter prospective study

To evaluate the influence of low-concentration contrast agents and low-tube-voltage computed tomography on chest enhancement examinations, we conducted a multicenter prospective study. A total of 216 inpatients enrolled from 12 different hospitals were randomly divided into four groups: A: voltage, 120 kVp; iohexol, 350 mgI/mL; B: voltage, 100 kVp, iohexol, 350 mgI/mL; C: voltage, 120 kVp, iodixanol, 270 mgI/mL; and D: voltage, 100 kVp, iodixanol, 270 mgI/mL. Subjective image quality was assessed by two radiologists and compared by weighted kappa test. The objective image scores, scanning radiation doses, and pathological coincidence rates were analyzed. There were no significant differences in gender, age, height, weight, and body mass index between the four groups (p > 0.05). The consistency of the radiologists' ratings were good, with kappa value ranging from 0.736 (95% confidence interval: 0.54-0.933) to 0.809 (95% confidence interval: 0.65-0.968), and there was no difference in subjective image score between the four groups. The computed tomography value of group D had no difference with group A. The volume computed tomography dose index, dose length product, and effective dose of group D (6.93 ± 3.03, 241.55 ± 104.75, and 3.38 ± 1.47, respectively) were all significantly lower than those of group A (10.30 ± 4.37, 359.70 ± 152.65, and 5.04 ± 2.14, respectively). There was no significant difference in the imaging diagnosis accuracy rate between the four groups (p > 0.05). The results indicated that low-concentration contrast agents (270 mgI/mL) and low-tube-voltage (100 kVp) computed tomography can not only decrease radiation dose but also guarantee the image quality and meet the needs of imaging diagnosis in chest enhancement examinations, which make it possible for its generalization and application.

Preoperative assessment of contrast-enhanced spectral mammography of diagnosed breast cancers after sonographic biopsy: Correlation to contrast-enhanced magnetic resonance imaging and 5-year postoperative follow-up

To assess the feasibility of using contrast-enhanced spectral mammography (CESM) for operative planning of patients with breast cancers who were initially diagnosed by sonographic guided biopsy.With the approval of the Institutional Review Board of our hospital, we retrospectively reviewed the data on patients with breast cancers who underwent CESM and contrast-enhanced magnetic resonance imaging (CE-MRI) prior to operation and were followed up for at least 5 years postoperatively. The patients with breast cancer diagnosed by sonographic guided biopsy without mammography were included for analysis. The size and number of cancers on low-energy mammograms (LE-MG), recombined subtracted mammograms (RSM), and CE-MRI were recorded and compared with microscopic histopathologic data and at least 5 years of clinical follow-up data.Fifty-one cancerous breasts of 46 patients were included in the analysis. All the principal cancers could be detected by RSM or CE-MRI; however, only 45 were by LE-MG. The Pearson correlation coefficients for the size on microscopy were 0.44 for LE-MG, 0.77 for RSM, and 0.84 for CE-MRI (all P-values ≤.001). Regarding the microscopic reports, RSM or CE-MRI had sensitivities of 100% and a positive predictive value of 63.6% for multicentric cancers. One breast cancer with partial mastectomy recurred after 3 years of follow-up.CESM was feasible for assessing the cancer extension and multicentric cancers as secondary examination in patients with diagnosed breast cancers after sonographic biopsy.

Incidentally detected biliary ductal dilatation on contrast-enhanced CT: what is the incidence of occult obstructing malignancy?

PURPOSE

The purpose of this study was to determine the incidence of occult obstructing malignancy in the setting of asymptomatic biliary ductal dilatation incidentally detected and without identifiable cause on contrast-enhanced CT.

METHODS

A retrospective search identified patients with biliary ductal dilatation on contrast-enhanced CT from March 30, 2007 to November 1, 2017. Patients with biliary symptomatology or clinical concern for an obstructing process, an explanation for biliary ductal dilatation on index CT, intrahepatic without extrahepatic biliary ductal dilatation, concurrent pancreatic ductal dilatation, and inadequate follow-up were excluded. A reference standard of at least 1 year of imaging follow-up or 2 years of clinical follow-up was used to exclude occult obstructing malignancy.

RESULTS

156 patients were included; 120 patients met imaging follow-up criteria and 36 patients met clinical follow-up criteria. No cases of occult malignancy were identified as the source of biliary ductal dilatation (95% CI 0.0-1.9%). LFTs were available for 131 patients, of which 36 were elevated (27%). One case demonstrated a 1.2-cm ampullary adenoma on endoscopic retrograde cholangiopancreatography (occult on follow-up MRI, normal LFTs at the time of the index CT).

CONCLUSION

Asymptomatic biliary ductal dilatation incidentally detected and without identifiable cause on contrast-enhanced CT is likely benign in patients with normal LFTs, and further workup may not be warranted.

Coronary Microvascular Dysfunction by Myocardial Contrast Echocardiography in Nonelderly Patients Referred for Computed Tomographic Coronary Angiography

BACKGROUND

Microvascular dysfunction (MVD) is a potential cause of chest pain in younger individuals. The authors hypothesized that nonelderly patients referred for computed tomographic angiography (CTA) but without significant stenosis would have a high prevalence of MVD by myocardial contrast echocardiography (MCE). Secondary aims were to test whether the presence of nonobstructive coronary artery disease (CAD) or reduced brachial flow-mediated dilation (FMD) predicted MVD.

METHODS

Subjects ≤60 years of age undergoing CTA were recruited if they had either no evidence of coronary plaque or evidence of mild CAD (<50% stenosis) and at least one high-risk plaque feature. Subjects underwent quantitative perfusion imaging using MCE at rest and during regadenoson vasodilator stress. MVD was defined as global or segmental delay of microvascular refill (≥2 sec) during regadenoson. FMD of the brachial artery was also performed.

RESULTS

Of the 29 patients in whom MCE could be performed, 12 (41%) had MVD. These subjects, compared with those with normal microvascular function, had lower hyperemic perfusion (mean, 236 ± 68 vs 354 ± 161 intensity units/sec; P = .02) and microvascular flux rate (mean, 1.6 ± 0.4 vs 2.5 ± 0.9 sec-1; P = .002) on quantitative MCE. The degree of FMD was not significantly different in those with or without MVD (mean, 11 ± 4% vs 9 ± 4%; P = .32), and there was a poor correlation between results on stress MCE and FMD. Only eight of the 29 subjects were classified as having nonobstructive CAD. There were no groupwise differences in the prevalence of MVD function in those with versus without CAD (43% vs 38% for negative and positive findings on CTA, respectively, P = .79).

CONCLUSIONS

MVD is a common finding in the nonelderly population referred for CTA for evaluation of possible CAD but without obstructive stenosis. Neither the presence of noncritical atherosclerotic disease nor abnormal FMD increases the likelihood for detecting MVD in this population.

CT Colonography in Preoperative Staging of Colon Cancer: Evaluation of FOxTROT Inclusion Criteria for Neoadjuvant Therapy

OBJECTIVE

The purpose of the present study is to evaluate the diagnostic performance of and interreader agreement for CT colonography (CTC) in the local staging of colon cancer, with emphasis given to the FOxTROT (Fluoropyrimidine, Oxaliplatin, and Targeted-Receptor pre-Operative Therapy [Panitumumab]) trial inclusion criteria, which propose a new tailored treatment paradigm for colon cancer that uses neoadjuvant therapy for patients with a high-risk of locoregional disease as determined by imaging.

MATERIALS AND METHODS

This biinstitutional retrospective study involved 89 patients (with 93 tumors) who had colon cancer and underwent presurgical CTC. Two radiologists reviewed the CTC studies for local staging, including measurement of the tumor beyond the muscularis propria on a true orthogonal plane. Histopathologic findings for surgical colectomy specimens served as the reference standard for local pathologic staging. The sensitivity, specificity, positive predictive value, and negative predictive value for local determination of the T category, N category, and extramural vascular invasion (EMVI) were calculated separately for each reader. High-risk T category tumors were the same as those as used in the FOxTROT trial. Interreader agreement was assessed using the kappa statistic.

RESULTS

Thirty-five of 93 tumors (37.6%) were histologically classified as high-risk tumors (T3c, T3d, or T4 tumors). The interreader agreement was substantial (κ = 0.68) for classifying high-risk tumors with the use of CTC, moderate for differentiating N0 from N1 and N2 (κ = 0.44), and slight for detecting EMVI (κ = 0.15). The diagnostic statistics for CTC for the two readers were as follows: for detection of high-risk tumors, sensitivity was 65.7% and 82.9%, and specificity was 81.0% and 87.9%; for detection of N category-positive disease, sensitivity was 50.9% and 69.8%, and specificity was 50.0% and 72.5%; and for detection of EMVI, sensitivity was 18.2% and 66.7%, and specificity was 60.0% and 91.7%.

CONCLUSION

The present study shows that CTC might be a feasible imaging modality for preoperative local staging of higher-risk colon cancers for which neoadjuvant chemotherapy is more suitable on the basis of the FOxTROT trial criteria. However, further studies are required to allow a better generalization of our results.

Bedside Iohexol Ventriculography for Patients with Obstructive Colloid Cysts: A Protocol to Identify Auto-Fenestration of the Septum Pellucidum

OBJECTIVE

Patients with hydrocephalus secondary to third ventricular colloid cysts can require bilateral external ventricular drain (EVD) placement while awaiting surgery. However, some patients could develop auto-fenestration of the septum pellucidum (AFSP) and only require 1 EVD. We evaluated our experience with bedside iohexol ventriculography and staged EVD placement for patients with obstructive hydrocephalus.

METHODS

We retrospectively identified 34 patients who had been treated for third ventricular colloid cysts (2013-2016). The preoperative and postoperative data, including age, sex, colloid cyst size, preoperative hydrocephalus, preoperative EVD placement, preoperative iohexol ventriculography, operative approach, intraoperative findings, and postoperative ventriculoperitoneal shunt requirements, were reviewed.

RESULTS

Hydrocephalus was found in 23 patients (68%) on initial presentation. Nine patients (26%) had EVDs placed before surgery. Six patients (18%) underwent iohexol ventriculography after insertion of a right-sided EVD. Five patients (15%) demonstrated no evidence of ventricular communication. Four patients (67%) required left-sided EVD placement. One patient (17%) had robust communication between the lateral ventricles after intraventricular iohexol injection, which was managed with a single EVD. AFSP was observed during surgical resection of this patient's colloid cyst. One other patient who did not undergo preoperative EVD placement was noted to have AFSP intraoperatively, resulting in 2 of 34 patients (6%) with AFSP in our series.

CONCLUSIONS

A subset of patients with obstruction at the foramina of Monro can develop AFSP. Iohexol ventriculography after unilateral EVD placement allows clinicians to assess for the presence of AFSP and identify patients who can be treated with a single EVD before surgery.

Assessment of the origin and transport of four selected emerging micropollutants sucralose, Acesulfame-K, gemfibrozil, and iohexol in a karst spring during a multi-event spring response

The assessment of vulnerability in karst systems reveals to be extremely challenging since it varies significantly with time and highly depends on the identification of diffuse and concentrated infiltration from surface karst features. The origin, consumed loads, and transport mode of selected micropollutants (MPs) including two artificial sweeteners (ASWs) Sucralose (SUC) and Acesulfame-K (ACE-K), in addition to other less investigated pharmaceuticals such as the lipid regulator Gemfibrozil (GEM), and the contrast media Iohexol (IOX) were investigated in a karst system under dynamic conditions. A detailed analysis of selected spring responses' chemograph and hydrograph following a multi precipitation event shows that three of the tracked MPs, especially ACE-K, and to the exception of IOX, can be used as specific indicators for point source domestic wastewater in karst systems. They have revealed to be persistent, source specific, conservative, and highly correlated with in-situ parameters easily measurable at the spring (chloride and turbidity). Even if the selected MPs are found in the system during low flow periods, they are mostly transported to the spring through fast flow pathways from flushed wastewater with surface water or flood rainwater. The highest mass inflow of ACE-K, IOX and GEM originated from a sinking stream, while SUC infiltrated exclusively through fast infiltration points (dolines). Their breakthrough curves coincide with the arrival of new waters and turbidity peaks. Unlike IOX, the mass fluxes of ASWs, and GEM to a lesser extent, can be linearly correlated with chloride mass fluxes and turbidity flux. Moreover, the variance of the normalized breakthrough curves of the MPs with respect to a mean transit time, increases in that order IOX<GEM<Turbidity<SUC<ACE-K indicating a higher restitution time for ACE-K with respect to other spring signals.

Extensive Thrombus and Brain Microabscesses After Sleeve Gastrectomy

Sleeve gastrectomy is a relatively newer bariatric surgical procedure and has become the most common of all bariatric surgeries performed. Complication rates reported with sleeve gastrectomies are relatively low and are generally due to staple line leaks, hemorrhage, or sleeve stricture. Portal vein thrombosis is an uncommon but potentially dangerous complication. We present a case of a 21-year-old woman who developed thrombosis of the portal, splenic, and right common iliac veins that then resulted in multifocal brain abscesses from presumed Fusobacterium septic emboli following an uncomplicated laparoscopic sleeve gastrectomy.

Internal Hernia in Pregnant Woman after Roux-en-Y Gastric Bypass Surgery

Laparoscopic Roux-en-Y gastric bypass has become the most common obesity surgery procedure worldwide over the last two decades. Many patients undergoing the procedure are women of reproductive age. This carries a risk for developing gastric bypass-related complications during pregnancy. One of the potentially serious risks is an internal hernia. We present a patient in the third trimester of pregnancy with an internal hernia following a laparoscopic Roux-en-Y gastric bypass for morbid obesity. We discuss the importance of computed tomography (CT) in the diagnosis of an internal hernia and review key CT findings including compression of the superior mesenteric vein, which proved to be crucial in diagnosing the internal hernia in this patient.

Endovascular treatment of cerebral aneurysm after renal transplantation in polycystic kidney disease

Background Patients with polycystic kidney disease have a higher prevalence of intracranial aneurysms and may progress to renal failure requiring transplantation. The endovascular treatment of intracranial aneurysms may improve prognosis, since rupture often causes premature death or disability, but the nephrotoxicity risk associated with contrast medium must be always considered in cases of renal impairment. Methods A 55-year-old female patient with polycystic kidney disease and grafted kidney associated with anterior communicant artery aneurysm was successfully treated by embolization. Results The renal function remained normal after the procedure. To the authors' knowledge, this is the first case of endovascular treatment of brain aneurysm in a transplanted patient reported in the medical literature. Conclusions The endovascular procedure in renal transplant patients is feasible and can be considered to treat this population. Further studies and cases are needed to confirm its safety.

Torsion of a Myomatous, Non-gravid Uterus: CT Findings

Uterine torsion is a rare condition which is part of a spectrum of gynecological emergencies. If diagnosis is delayed or the condition is left untreated, severe consequences such as infertility and life-threatening complications can arise. As presenting features are often non-specific and can be similar to commonly encountered gastrointestinal and urinary conditions, computed tomography is usually the first imaging modality utilized in an emergency setting. It is therefore important that the radiologist is familiar with recognizing computed tomography features of uterine torsion. We share our findings in a patient with uterine torsion in a non-gravid uterus, diagnosed on contrast-enhanced computed tomography with multiplanar reconstruction.

Applicability of current NCCN Guidelines for pancreatic adenocarcinoma resectability: analysis and pitfalls

PURPOSE

To test the applicability of National Comprehensive Cancer Network (NCCN v 3.2017) resectability criteria for pancreatic ductal adenocarcinoma (PDAC) in clinical practice, at a high-volume tertiary referral center.

MATERIALS AND METHODS

102 consecutive patients (53 female; mean age 66.2 years, range 34-90 years) with biopsy proven, non-metastatic PDAC were evaluated by our multidisciplinary pancreatic cancer program between July 2013 and February 2016. Retrospective review of staging pancreatic CT angiography was performed, and radiographic features were categorized as conforming to or non-conforming to existing v 3.2017 definitions.

RESULTS

Among 102 patients, 10 (10%) had CTA evidence of vascular involvement that did not conform to existing NCCN Guidelines. Six new scenarios of vascular involvement were identified. The remaining 92 patients presented with resectable (n = 20 [22%]), borderline resectable (n = 42 [45.6%]), or unresectable (n = 30 [33%]) PDAC. Approximately half (n = 21 [51%]) of borderline resectable patients' tumors demonstrated isolated venous involvement, whereas 39% had both arterial and venous involvement. A minority (11%) demonstrated only major arterial involvement. Assignment to unresectable status reflected both arterial and venous involvement (11, 37%), arterial involvement only (10, 33%) patients, and unreconstructible venous involvement in 9 (30%).

CONCLUSION

In our experience, current NCCN resectability guidelines for PDAC do not accurately classify vascular involvement identified in approximately 10% of patients. Revision of the current guidelines could be helpful to clinical practice.

Optic Nerve Sheath Dural Arteriovenous Fistula Misdiagnosed As A Carotid Cavernous Fistula

Dural arteriovenous fistulas (dAVf) are uncommon, acquired vascular lesions. Their location and vascular anatomy produces varied signs and symptoms and are misdiagnosed as other vascular anomalies. We present an atypical case of a dAVf identified along the left optic nerve sheath. The patient presented with progressive ophthalmological signs and was initially misdiagnosed with a left carotid-cavernous fistula. The aetiology, classification and treatment options are discussed.

Tarsometatarsal joint communication during fluoroscopy-guided therapeutic joint injections and relationship with patient age and degree of osteoarthritis

OBJECTIVE

Although the tarsometatarsal joints are separated into three distinct synovial compartments, communications between adjacent compartments are often noted during image-guided injections. This study aims to determine whether abnormal inter-compartment tarsometatarsal joint communication is associated with patient age or degree of tarsometatarsal osteoarthritis.

MATERIALS AND METHODS

One hundred forty tarsometatarsal injections were retrospectively reviewed by two radiologists. Extent of inter-compartment communication and degree of osteoarthritis were independently scored. Univariate and multivariable analyses were performed to assess whether the presence of and number of abnormal joint communications were related to age and degree of osteoarthritis.

RESULTS

Forty out of 140 tarsometatarsal joints showed abnormal communication with a separate synovial compartment, and 3 of the 40 showed abnormal communication with two separate compartments. On univariate analysis, higher grade osteoarthritis (p < 0.001) and older age (p = 0.014) were associated with an increased likelihood of abnormal inter-compartment tarsometatarsal communication and a greater number of these abnormal communications. On multivariate analysis, the degree of osteoarthritis remained a significant predictor of the presence of (p < 0.001) and number of (p < 0.001) abnormal communications, while the association of age was not statistically significant. There was significant correlation between age and degree of osteoarthritis (p < 0.001).

CONCLUSION

Higher grade osteoarthritis increases the likelihood of abnormal inter-compartment tarsometatarsal joint communication and is associated with a greater number of abnormal communications. Diagnostic injection to localize a symptomatic tarsometatarsal joint may be less reliable in the setting of advanced osteoarthritis.

Large septic pulmonary embolus complicating streptococcus mutans pulmonary valve endocarditis

Large septic pulmonary embolus is a rare finding in right-sided endocarditis. The entity represents a challenging diagnosis due to its variable and nonspecific clinical and radiological presentation and similarities with other conditions. We present a case of a 41 year-old woman who developed a large main pulmonary artery embolus and bilateral cavitary lung nodules in the setting of severe sepsis. Pulmonary artery exploration and clot retrieval ultimately revealed a large septic embolus from Streptococcus mutans native pulmonary valve endocarditis. The diagnosis of septic pulmonary emboli from right-sided endocarditis should be considered in patients with ancillary findings of septic embolic phenomenon, particularly the presence of multifocal cavitary nodules and in the setting of appropriate predisposing factors.

Correlation Between Contrast Time-Density Time on Digital Subtraction Angiography and Flow: An in Vitro Study

BACKGROUND AND PURPOSE

Digital subtraction angiography (DSA) provides an excellent anatomic characterization of cerebral vasculature, but hemodynamic assessment is often qualitative and subjective. Various clinical algorithms have been produced to semiquantify flow from the data obtained from DSA, but few have tested them against reliable flow values.

METHODS

An arched flow model was created and injected with contrast material. Seventeen injections were acquired in anterior-posterior and lateral DSA projections, and 4 injections were acquired in oblique projection. Image intensity change over the angiogram cycle of each DSA run was analyzed through a custom MATLAB code. Time-density plots obtained were divided into 3 components (time-density times, TDTs): TDT_10%-100% (time needed for contrast material to change image intensity from 10% to 100%), TDT_100%-10% (time needed for contrast material to change image intensity from 100% to 10%), and TDT_25%-25% (time needed for contrast material to change from 25% image intensity to 25%). Time-density index (TDI) was defined as model cross-sectional area to TDT ratio, and it was measured against different flow rates.

RESULTS

TDI_10%-100%, TDI_100%-10%, and TDI_25%-25% all correlated significantly with flow (P < 0.001). TDI_10%-100%, TDI_100%-10%, and TDI_25%-25% showed, respectively, a correlation coefficient of 0.91, 0.91, and 0.97 in the anterior-posterior DSA projections (P < 0.001). In the lateral DSA projection, TDI_100%-10% showed a weaker correlation (r = 0.57; P = 0.03). Also in the oblique DSA projection, TDIs correlated significantly with flow.

CONCLUSIONS

TDI on DSA correlates significantly with flow. Although in vitro studies might overlook conditions that occur in patients, this method appears to correlate with the flow and could offer a semiquantitative method to evaluate the cerebral blood flow.

Distribution and relevance of iodinated X-ray contrast media and iodinated trihalomethanes in an aquatic environment

Distribution and relevance of iodinated X-ray contrast media (ICM) and iodinated disinfection byproducts (I-DBPs) in a real aquatic environment have been rarely documented. In this paper, some ICM were proven to be strongly correlated with I-DBPs through investigation of five ICM and five iodinated trihalomethanes (I-THMs) in surface water and two drinking water treatment plants (DWTPs) of the Yangtze River Delta, China. The total ICM concentrations in Taihu Lake and the Huangpu River ranged from 88.7 to 131 ng L^-1 and 102-252 ng L^-1, respectively. While the total I-THM concentrations ranged from 128 to 967 ng L^-1 in Taihu Lake and 267-680 ng L^-1 in the Huangpu River. Iohexol, the dominant ICM, showed significant positive correlation (p < 0.01) with CHClI₂ in Taihu Lake. Iopamidol and iomeprol correlated positively (p < 0.01) with some I-THMs in the Huangpu River. The observed pronounced correlations between ICM and I-THMs indicated that ICM play an important role in the formation of I-THMs in a real aquatic environment. Characteristics of the I-THM species distributions indicated that I-THMs may be transformed by natural conditions. Both DWTPs showed negligible removal efficiencies for total ICM (<20%). Strikingly high concentrations of total I-THMs were observed in the finished water (2848 ng L^-1 in conventional DWTP and 356 ng L^-1 in advanced DWTP). Obvious transformation of ICM to I-THMs was observed during the chlorination and ozonization processes in DWTPs. We suggest that ICM is an important source for I-DBP formation in the real aquatic environment.