The Use of Ultrasound-Measured Optic Nerve Sheath Diameter to Predict Ventriculoperitoneal Shunt Failure in Children.

OBJECTIVE: The goal of this study was to assess the accuracy of ultrasound-measured optic nerve sheath diameter (ONSD) as a screen for ventriculoperitoneal shunt failure. METHODS: We prospectively enrolled a convenience sample of children presenting to the ED with suspected shunt failure. The ONSD was measured by ultrasound and compared with computed tomography/magnetic resonance imaging (CT/MRI) and neurosurgical impression. We defined shunt failure on ultrasound as an ONSD greater than 4.0 mm in infants 12 months and younger or greater than 4.5 mm in children older than 12 months. A single emergency radiologist at our institution read all CTs and MRIs for categorical determination of shunt failure. We defined shunt failure based on neurosurgical impression as a decision to admit and perform shunt revision. We report test characteristics and 95% confidence intervals of ONSD as a predictor for shunt failure. RESULTS: We enrolled 32 subjects. The sensitivities of ONSD compared with CT/MRI and neurosurgical impression, 60.0% and 75.0%, respectively, were low. However, the negative predictive values of ONSD compared with CT/MRI and neurosurgical impression were 90.0% and 95.0%, respectively. CONCLUSIONS: Optic nerve sonography may be a useful tool to identify children presenting with suspected ventriculoperitoneal shunt failure who do not require further imaging. This would reduce the use of CT scan and exposure to ionizing radiation in children with suspected shunt malfunction who do not require neurosurgical intervention. Consideration of additional risk factors and a larger sample size may yield stronger results.

Emergency color Doppler sonography of the extremity artery: A pictorial essay.

Arterial color duplex sonography (CDUS) of the extremities is routinely analyzed in the field of emergency radiology. A retrospective review of 500 consecutive arterial CDUS extremity studies was performed in our emergency department. Abnormal CDUS examinations were classified into two groups according to their primary etiology: 1) traumatic arterial injuries (accidents or post-operative complications) and 2) acute arterial ischemia (thrombosis or embolism outside of the setting of acute trauma). This article reviews common CDUS imaging findings in a busy emergency radiology division including traumatic pseudoaneurysm, secondary pseudoaneurysm, arteriovenous fistula, acute ischemic arterial disease and chronic peripheral arterial disease. This essay highlights the crucial role of CDUS in the diagnosis of vascular abnormalities in the emergency setting. CDUS provides several advantages over other imaging modalities including high accuracy, rapid results, portability, lack of radiation, and low cost.

Imaging Findings in Elder Abuse: A Role for Radiologists in Detection.

PURPOSE: Emergency department assessment represents a critical but often missed opportunity to identify elder abuse, which is common and has serious consequences. Among emergency care providers, diagnostic radiologists are optimally positioned to raise suspicion for mistreatment when reviewing imaging of geriatric injury victims. However, little literature exists describing relevant injury patterns, and most radiologists currently receive neither formal nor informal training in elder abuse identification. METHODS: We present 2 cases to begin characterisation of the radiographic findings in elder abuse. RESULTS: Findings from these cases demonstrate similarities to suspicious findings in child abuse including high-energy fractures that are inconsistent with reported mechanisms and the coexistence of acute and chronic injuries. Specific injuries uncommon to accidental injury are also noted, including a distal ulnar diaphyseal fracture. CONCLUSIONS: We hope to raise awareness of elder abuse among diagnostic radiologists to encourage future large-scale research, increased focus on chronic osseous findings, and the addition of elder abuse to differential diagnoses.

Radiologists' Training, Experience, and Attitudes About Elder Abuse Detection.

OBJECTIVE: Elder abuse is underrecognized, and identification of subtle cases requires a high index of suspicion among all health care providers. Because many geriatric injury victims undergo radiographic imaging, diagnostic radiologists may be well positioned to identify injury patterns suggestive of abuse. Little is known about radiologists' experience with elder abuse. Our goal was to describe knowledge, attitudes, training, and practice experience in elder abuse detection among diagnostic radiologists. SUBJECTS AND METHODS: We conducted 19 interviews with diagnostic radiologists at a large urban academic medical center using a semistructured format. Data from these sessions were coded and analyzed to identify themes. RESULTS: Only two radiologists reported any formal or informal training in elder abuse detection. All subjects believed they had missed cases of elder abuse. Even experienced radiologists reported never having received a request from a referring physician to assess images for evidence suggestive of elder abuse. All subjects reported a desire for additional elder abuse training. Also, subjects identified radiographic findings or patterns potentially suggestive of elder abuse, including high-energy injuries such as upper rib fractures, injuries in multiple stages of healing, and injuries inconsistent with reported mechanism. CONCLUSION: Radiologists are uniquely positioned to identify elder abuse. Though training in detection is currently lacking, providers expressed a desire for increased knowledge. In addition, radiologists were able to identify radiographic findings suggestive of elder abuse. On the basis of these findings, we plan to conduct additional studies to define pathognomonic injury patterns and to explore how to empower radiologists to incorporate detection into their practice.

Prospective Cohort Study of Nephrogenic Systemic Fibrosis in Patients With Stage 3-5 Chronic Kidney Disease Undergoing MRI With Injected Gadobenate Dimeglumine or Gadoteridol.

OBJECTIVE: The purpose of this study was to determine the incidence of nephrogenic systemic fibrosis (NSF) in patients with chronic kidney disease (CKD) and moderate-to-severe impairment of kidney function who had not previously been exposed to gadolinium-based contrast agents (GBCAs) or referred to undergo contrast-enhanced MRI with gadobenate dimeglumine or gadoteridol. SUBJECTS AND METHODS: Two multicenter prospective cohort studies evaluated the incidence of unconfounded NSF in patients with stage 3 CKD (estimated glomerular filtration rate [eGFR] in cohort 1, 30-59 mL/min/1.73 m(2)) or stage 4 or 5 CKD (eGFR in cohort 2, < 30 mL/min/1.73 m(2)) after injection of gadobenate dimeglumine (study A) or gadoteridol (study B). A third study (study C) determined the incidence of NSF in patients with stage 4 or 5 CKD who had not received a GBCA in the 10 years before enrollment. Monitoring for signs and symptoms suggestive of NSF was performed via telephone at 1, 3, 6, and 18 months, with clinic visits occurring at 1 and 2 years. RESULTS: For studies A and B, the populations evaluated for NSF comprised 363 and 171 patients, respectively, with 318 and 159 patients in cohort 1 of each study, respectively, and with 45 and 12 patients in cohort 2, respectively. No signs or symptoms of NSF were reported or detected during the 2 years of patient monitoring. Likewise, no cases of NSF were reported for any of the 405 subjects enrolled in study C. CONCLUSION: To our knowledge, and consistent with reports in the literature, no association of gadobenate dimeglumine or gadoteridol with unconfounded cases of NSF has yet been established. Study data confirm that both gadoteridol and gadobenate dimeglumine properly belong to the class of GBCAs considered to be associated with the lowest risk of NSF.

Morphine three-dimensional T1 gadoxetate MR cholangiography of potential living related liver donors.

PURPOSE: To assess low-dose morphine for distension and improved visualization of intrahepatic bile ducts on T1 MR cholangiography (MRC) in preoperative imaging of potential liver donors. MATERIALS AND METHODS: Sixty-nine consecutive potential living related liver donors (mean age, 39 years; age range, 20 to 59 years) referred for pre-transplant MRI evaluation were evaluated without (n=30) or with (n=39) intravenous morphine injection (0.04 mg/kg). Morphine was injected pre-MRI while establishing intravenous access to allow ∼1 h for biliary distension before T1 MRC. Three radiologists reviewed intrahepatic biliary branch order visualization, common bile duct (CBD) diameter, and overall image quality. In 25 patients undergoing liver donation surgery, T1 MRC findings were correlated with intraoperative findings. This retrospective study was approved by the institutional review board. RESULTS: Biliary visualization was improved post-morphine administration with biliary duct branch order visualization score of 3.2 and 3.3 at 45 and 60 min, respectively, compared with 2.7 without morphine (P<0.002); CBD diameter measured 5.3 and 5.5 versus 4.1 mm (P<0.005), and overall image quality score was 2.4 and 2.6 versus 1.8 (P<0.0006). Operative notes confirmed T1 MRC findings in 6/11 donors without morphine and 14/14 donors with morphine. CONCLUSION: Intravenous low-dose morphine distends and improves visualization of bile ducts on T1 gadoxetate MRC.

Green tagging in displaying color Doppler aliasing: a comparison to standard color mapping in renal artery stenosis.

To quantitatively assess the contrast-to-noise ratio (CNR) of green tagging and standard color flow images in displaying fast flow velocity, we retrospectively reviewed 20 cases of hemodynamically significant renal artery stenosis (RAS) detected by renal color Doppler ultrasound and confirmed with digital subtraction angiography. At the site of RAS, blood flow with high velocity that appeared as aliasing on color flow images was computationally analyzed with both green tagging and standard color mapping. To assess the difference in the CNR between normal background flow and the aliased signal as a function of visualizing aliasing between the two color mappings, we used GetColorpixels (Chongqing Medical University, Chongqing, China) to count the values in the color channels after segmenting color pixels from gray-scale pixels. We then calculated the CNR in each color channel-red, green, and blue (RGB)--in the aliasing region on green tagging and standard color mapping. The CNRs in the red, green and blue channels were 0.35 ± 0.44, 1.11 ± 0.41 and 0.51 ± 0.19, respectively, on standard color mapping, and 0.97 ± 0.80, 4.01 ± 1.36 and 0.64 ± 0.29, respectively, on green tagging. We used a single-factor analysis of variance and two-tailed t-test to assess the difference in CNR in each color channel between the two color mappings at the site of RAS. With these comparisons, there was no significant difference in the CNR in the red or blue channel between green tagging and standard color mapping (p > 0.05). However, there was a statistically significant difference in the CNR in the green channel between the two color mappings (p = 0.00019). Furthermore, the CNR measured in the green channel on the green tagging image was significantly higher than the CNRs in all other color channels on both color mapping images (p = 0.000). Hence, we conclude that green tagging has significantly higher visibility as a function of high-velocity flow than standard color mapping. The use of green tagging may improve the ability to detect RAS with color Doppler ultrasound.

Longitudinal monitoring of cardiac siderosis using cardiovascular magnetic resonance T2* in patients with thalassemia major on various chelation regimens: a 6-year study.

Cardiovascular magnetic resonance (CMR) and hepatic magnetic resonance imaging (MRI) have become reliable noninvasive tools to monitor iron excess in thalassemia major (TM) patients. However, long-term studies are lacking. We reviewed CMR and hepatic MRI T2* imaging on 54 TM patients who had three or more annual measurements. They were managed on various chelation regimens. Patients were grouped according to their degree of cardiac siderosis: severe (T2*, <10 msec), mild to moderate (T2* = 10-20 msec), and no cardiac siderosis (T2*, >20 msec). We looked at the change in cardiac T2*, liver iron concentration (LIC) and left ventricular ejection fraction (LVEF) at years 3 and 5. In patients with severe cardiac siderosis, cardiac T2* (mean ± SD) improved from 6.9 ± 1.6 at baseline to 13.6 ± 10.0 by year 5, mean ΔT2* = 6.7 (P = 0.04). Change in cardiac T2* at year 3 was not significant in the severe group. Patients with mild to moderate cardiac siderosis had mean cardiac T2* of 14.6 ± 2.9 at baseline which improved to 26.3 ± 9.5 by year 3, mean ΔT2* = 1.7 (P = 0.01). At baseline, median LICs (mg/g dry weight) in patients with severe, mild-moderate, and no cardiac siderosis were 3.6, 2.8, and 3.3, whereas LVEFs (mean ± SD) (%) were 56.3 ± 10.1, 60 ± 5, and 66 ± 7.6, respectively. No significant correlation was noted between Δ cardiac T2* and Δ LIC, Δ cardiac T2*, and Δ LVEF at years 3 and 5. Throughout the observation period, patients with no cardiac siderosis maintained their cardiac T2* above 20 msec. The majority of patients with cardiac siderosis improve cardiac T2* over time with optimal chelation.

Improved hepatic arterial phase MRI with 3-second temporal resolution.

PURPOSE: To assess 3-s temporal resolution for arterial phase bolus timing on dynamic liver MRI. MATERIALS AND METHODS: One hundred consecutive patients undergoing fluoro-triggered dynamic gadoxetate enhanced liver MRI with standard Cartesian k-space LAVA (Liver Acquisition with Volume Acceleration) were compared with 61 consecutive patients imaged using spiral k-space LAVA reconstructed at 3-s temporal resolution with sliding window reconstruction. For qualitative analysis, bolus timing, hepatic artery branch order visualized, and overall image quality were evaluated. For quantitative analysis, contrast to noise ratio between aorta and liver parenchyma, aorta and portal vein, and signal intensity ratio between aorta and liver parenchyma were calculated. RESULTS: MR fluoroscopy triggered single phase standard LAVA produced optimal arterial phase timing in 35% patients, compared with 88% with Spiral LAVA (P < 0.0001). Spiral LAVA had superior bolus timing scoring 2.0, compared with 1.0 with standard LAVA (P < 0.0001). Overall image quality and hepatic artery branch order visualization scoring were superior on spiral LAVA, compared with standard LAVA (P < 0.001). The aorta to liver parenchyma signal intensity ratio was also superior on spiral LAVA, compared with standard LAVA (2.8 vs. 2.2; P < 0.001). CONCLUSION: Dynamic liver MRI bolus timing improves using 3-s temporal resolution.

Clinical demand for chest/abdomen/pelvis anatomy following thoracic or lumbar spine CT.

The purpose of this study is to determine how often CT is repeated to obtain chest/abdomen/pelvis data outside the reconstructed field of view (FOV) on a prior spine CT. Radiology records of 1,239 consecutive thoracic and lumbar spine CT exams of 1,025 patients from January 1, 2006 to December 31, 2008 were retrospectively reviewed to identify patients who subsequently had CT studies of the chest, abdomen, and/or pelvis. The CT data were also evaluated for contrast enhancement, slice thickness, radiation dose, and reason for subsequent CT exam. Over 3 years, 290 of the 1,239 (24%) spine CT exams were followed by CT of the same anatomic region to evaluate extraspinal anatomy. The use or nonuse of contrast in these follow-up studies was the same as the preceding spine study in 91 cases, which were repeated on the same day (n = 37), within 7 days (n = 19), within 8-30 days (n = 15), or after 30 days (n = 20). Fourteen of 25 (56%) T spine CTs and 34 of 52 (65%) L spine CTs without contrast were followed by a chest CT or abdomen/pelvis CT without contrast within 7 days, respectively. Among 31 pediatric exams, 6 of 31 (19%) spine CTs were followed by a CT of the same anatomic region, all within 7 days. Reconstructing full FOV images of spine CT scans in addition to the standard coned down spine FOV may reduce redundant CT imaging and radiation dose.

Doppler angle correction in the measurement of intrarenal parameters.

BACKGROUND: The aim of this study was to assess differences in intrarenal artery Doppler parameters measured without and with Doppler angle correction. METHODS: We retrospectively reviewed color duplex sonography in 30 normally functioning kidneys (20 native kidneys in 10 subjects and 10 transplanted kidneys in 10 subjects) performed between January 26, 2010 and July 26, 2010. There were 10 age-matched men and 10 age-matched women (mean 39.8 ± 12.2, range 21-60 years) in this study. Depending on whether the Doppler angle was corrected in the spectral Doppler measurement, Doppler parameters including peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI) measured at the interlobar artery of the kidney were divided into two groups, ie, initial Doppler parameters measured without Doppler angle correction (Group 1) and remeasured Doppler parameters with Doppler angle correction (Group 2). Values for PSV, EDV, and RI measured without Doppler angle correction were compared with those measured with Doppler angle correction, and were analyzed statistically with a paired-samples t-test. RESULTS: There were statistical differences in PSV and EDV at the interlobar artery in the upper, mid, and lower poles of the kidney between Group 1 and Group 2 (all P < 0.001). PSV and EDV in Group 1 were significantly lower than in Group 2. RI in Group 1 was the same as that in Group 2 in the upper, mid, and lower poles of the kidneys. CONCLUSION: Doppler angle correction plays an important role in the accurate measurement of intrarenal blood flow velocity. The true flow velocity converted from the maximum Doppler velocity shift is produced only when the Doppler angle is 0°, so that the emission sound beam is parallel to the direction of blood flow at the sampled artery. Therefore, the Doppler angle correction should be routinely applied and displayed on renal color duplex sonography.

Celiac artery trunk thrombosis: an unusual complication of pancreatitis diagnosed on MRI.

Celiac artery trunk thrombosis is a rare complication of pancreatitis. Only two other cases have been reported in the English-language literature. Here, we present the clinical and multimodality imaging findings for a woman with pancreatitis who had continued pain after normalization of pancreatic enzyme levels and was unexpectedly found to have occlusion of her celiac trunk on follow-up MRI. She was managed as an outpatient and had spontaneous resolution 2 weeks later.

Spontaneous resolution of an iatrogenic arterioportal fistula following portal-vein thrombosis.

A 64-year-male underwent a liver biopsy based on clinical concern for primary biliary cirrhosis. The biopsy, which yielded normal results, was uneventful, with no immediate postbiopsy complications. A later MRI demonstrated early opacification of the right portal vein on arterial-phase imaging, suggesting communication between the right hepatic artery and the right portal vein. A conservative, watchful management approach was taken. Followup imaging demonstrated a thrombus within the main portal vein, with resulting decreased flow through the fistula. Further followup demonstrated complete occlusion of the main portal vein, with cavernous transformation. The fistula at this time had completely resolved. This an example of spontaneous resolution of an arterioportal shunt secondary to a portal-vein thrombosis. Whether the portal-vein thrombosis was caused by altered flow dynamics within the main portal vein or an unrelated disorder is not certain. The patient had a prior history of deep venous thrombosis, but workup for a hypercoagulable state was negative.

Multimodality imaging of a neonatal wandering spleen.

Wandering spleen, a rare entity, is caused by the absence or laxity of the normal anchoring splenic ligaments. Only three neonatal cases have been reported in the English-language literature. We present the clinical and multimodality imaging findings of a newborn with laceration and hemorrhage of a wandering spleen. The course was complicated by the concurrent diagnosis of glucose-6-phosphate dehydrogenase deficiency, which confused the clinical picture when a falling hematocrit raised the question of rebleeding several days after presentation.

The value of specific MRI features in the evaluation of suspected placental invasion.

OBJECTIVE: The objective of this study was to determine imaging features that may help predict the presence of placenta accreta, placenta increta or placenta percreta on prenatal MRI scanning. SUBJECTS AND METHODS: A retrospective review of the prenatal MR scans of 10 patients with a diagnosis of placenta accreta, placenta increta or placenta percreta made by pathologic and clinical reports and of 10 patients without placental invasion was performed. Two expert MRI readers were blinded to the patients' true diagnosis and were asked to score a total of 17 MRI features of the placenta and adjacent structures. The interrater reliability was assessed using kappa statistics. The features with a moderate kappa statistic or better (kappa > .40) were then compared with the true diagnosis for each observer. RESULTS: Seven of the scored features had an interobserver reliability of kappa > .40: placenta previa (kappa = .83); abnormal uterine bulging (kappa = .48); intraplacental hemorrhage (kappa = .51); heterogeneity of signal intensity on T2-weighted (T2W) imaging (kappa = .61); the presence of dark intraplacental bands on T2W imaging (kappa = .53); increased placental thickness (kappa = .69); and visualization of the myometrium beneath the placenta on T2W imaging (kappa = .44). Using Fisher's two-sided exact test, there was a statistically significant difference between the proportion of patients with placental invasion and those without placental invasion for three of the features: abnormal uterine bulging (Rater 1, P = .005; Rater 2, P = .011); heterogeneity of T2W imaging signal intensity (Rater 1, P = .006; Rater 2, P = .010); and presence of dark intraplacental bands on T2W imaging (Rater 1, P = .003; Rater 2, P = .033). CONCLUSIONS: MRI can be a useful adjunct to ultrasound in diagnosing placenta accreta prenatally. Three features that are seen on MRI in patients with placental invasion appear to be useful for diagnosis: uterine bulging; heterogeneous signal intensity within the placenta; and the presence of dark intraplacental bands on T2W imaging.