Early Venous Phase Research Articles

Contrast-enhanced ultrasound features of histologically proven small (≤20 mm) liver metastases

Objective: We analyzed contrast-enhanced ultrasound (CEUS) features of histologically proved small (≤20 mm) liver metastases, in comparison to small (≤20 mm) hepatocellular carcinomas (HCC), to define the differentiate diagnoses value of CEUS in clinical practice.Material and methods: Eighty-two cases of small (≤20 mm) liver metastases and 84 cases of small (≤20 mm) HCC were retrospectively reviewed. All patients had CEUS images. Two radiologists assessed CEUS enhancement pattern and time of enhancement in consensus. Statistical analyses were performed using SPSS v.19.0 (SPSS Inc., Chicago, IL). The χ2 test and the independent sample t-test were used to compare the differences.Results: Comparing to small HCCs, rapid rim-like hyper-enhancement in arterial phase (56.1% in liver metastases vs. 2.3% in HCCs, p < .01), rapid wash-out and become hypo-enhancement in late arterial phase or early portal venous phase (96.4% in liver metastases vs. 22.6% in HCCs, p < .01) with central non-enhanced area in late phase were characteristic CEUS features of small metastases.Conclusions: CEUS imaging enhancement findings reliably offer typical signs of small liver metastases, differentiate effectively with small HCCs. CEUS can help to improve the diagnostic confidence of small liver metastases.

Dual Energy CT- Surrogate Quantitative Marker of Response to Targetted treatment in HCC

Background and Aim: Dual energy CT (DECT)– novel CT imaging technique at two different energies, can be used to discriminate between different materials (e.g., fat, calcium, iodine, and water), which are not allowed by conventional CT. The images reconstructed from these differential data, including iodine concentration maps, may provide diagnostic information beyond that obtainable with conventional CT Aim: To evaluate the supplementary value of dual energy CT to assess response in cirrhotic patients with HCC following targeted therapy. Methods: 20 patients with targeted therapies for dual energy CT (TACE/TARE/RFA) were evaluated. Iodine uptake(IU), derived from the iodine-based material-decomposition image and the iodine concentration ratio on the dual energy CT acquired during early portal venous phase was calculated by drawing regions of interest within the treated lesion, at the edge and within the surrounding liver parenchyma. Quantification of IU (absolute value for total IU (mg) and volume-normalized IU (mg/ml)) was based on semi-automatic tumor volume segmentation compared to the background liver. The decrease compared with baseline was calculated. Results: The mean normalized IU per patient within the treated lesion compared to the cirrhotic liver parenchyma -31%. Total IU per patient, combining both normalized IU and volume, showed the most pronounced decrease. Conclusion: DECT enables objective, easy and fast parameterization of tumor size and contrast medium uptake. DECT provides a quantitative method with which to analyze the treated lesions in the cirrhotic liver. The authors have none to declare.

Mass Dimension Evaluation of the Optic Nerve Head Microvascularity in Non-Glaucomatous Optic Neuropathies

In several diseases, fractal analysis has been proven useful to give contribution in diagnosis and prognosis of the patient and to improve treatments. In the present work we have evaluated the mass dimension of the vascular pattern of optic nerve head in non-glaucomatous optic neuropathic patients and healthy controls. Static fluorescein angiogram was performed and the images of the early venous phase were saved. A manual outline of the trajectories of the two-dimensional vascular network was performed down to vessels of 20 micron diameter, processed to threshold the vessel network without background interference and converted into an outline of single pixels and then the fractal analysis was performed. Mass dimension evaluation of the optic nerve head microvascularity was able to differentiate health condition vs. non-glaucomatous neuropathies (p<0.01), as well optic neuritis vs. nonarteritic anterior ischemic optic neuropathy (p<0.01), with high sensitivity and specificity (p<0.0001; p<0.0001). Mass dimension index shows a significantly increased vascular complexity of the optic nerve head in cases compared with controls, also permitting to distinguish between patients affected by optic neuritis vs. nonarteritic anterior ischemic optic neuropathy. This new, fast, unexpensive, methodology may be used in helping the clinician to perform the differential diagnosis between the pathologies and to study the effect of therapies during the follow up of the patient.

EFFECT OF SEDATION ON CONTRAST‐ENHANCED ULTRASONOGRAPHY OF THE SPLEEN IN HEALTHY DOGS

Contrast-enhanced ultrasound of the spleen enables the dynamic assessment of the perfusion of this organ, however, both subjective and quantitative evaluation can be strongly influenced by sedative agent administration. The purpose of this prospective, experimental study was to test effects of two sedative agents on splenic perfusion during contrast-enhanced ultrasound of the spleen in a sample of healthy dogs. Contrast-enhanced ultrasound of the spleen was repeated in six healthy Beagles following a cross-over study design comparing three protocols: awake, butorphanol 0.2 mg/Kg intramuscular (IM), and dexmedetomidine 500 μg/m(2) IM. After intravenous injection of a phospholipid stabilized sulfur hexafluoride microbubble solution (SonoVue®, Bracco Imaging, Milano, Italy), the enhancement intensity and perfusion pattern of the splenic parenchyma were assessed and perfusion parameters were calculated. Normal spleen was slightly heterogeneous in the early phase, but the parenchyma was homogeneous at a later phase. Sedation with butorphanol did not modify perfusion of the spleen. Dexmedetomidine significantly reduced splenic enhancement, providing diffuse parenchymal hypoechogenicity during the entire examination. Measured parameters were significantly modified, with increased arrival time (AT; (< 0.0001) and time to peak (TTP; P < 0.0001), and decreased peak intensity (PI; P = 0.0108), wash-in (P = 0.0014), and area under the curve (AUC; P = 0.0421). Findings supported the use of butorphanol and contraindicated the use of dexmedetomidine as sedatives for splenic contrast ultrasound procedures in dogs. Short-term and diffuse heterogeneity of the spleen in the early venous phase was determined to be a normal finding.

Dynamic contrast-enhanced ultrasound (DCE-US) for the characterization of hepatocellular carcinoma and cholangiocellular carcinoma.

In a prospective study, we compared the different perfusion kinetics of HCC and ICC using dynamic contrast-enhanced ultrasound (DCE-US). Patients with proven HCC and ICC were included. Three-minute video clips of CEUS examinations (CPS - low MI mode) after a bolus injection of 1.2 ml SonoVue were recorded and analyzed with quantification software (VueBox). Parameters for the arterial contrast enhancement [rise time (RT), time-to-peak (TTP)] towards portal venous contrast enhancement [mean transit time (local) (mTTl) and fall time (FT)] were quantified. Furthermore, contrast wash-out after peak enhancement (PE) (40 s, 80 s, 100 s and 120 s after PE) was compared between HCC and ICC. 43 patients with proven HCC (n = 23 HCC; cirrhosis n = 16) and ICC (n = 20 ICC; Cirrhosis n = 6) were examined. No statistical difference of the arterial DCEUS parameters was found between HCC and ICC. Contrast enhancement of the portal venous and late phases showed significantly lower values in the ICC group indicating early wash-out of the contrast agent: mTTl (p = 0.0209): HCC 118.4 s (SD± 88.4); ICC 64.8 s (SD± 49.7). FT (p = 0.0433): HCC 42.5 s (SD± 27.7); ICC 27.7 s (SD± 16.2). The percental loss of intensity at a definite time point after PE was significantly higher in ICC than in HCC lesions. DCE-US is able to detect and quantify differences in perfusion kinetics between HCC and ICC. Whereas arterial contrast enhancement patterns may overlap between HCC and ICC, a timed characterization of wash-out kinetics may offer an additional tool to characterize HCC and ICC. The presence of a rapid loss of signal intensity in the early portal venous phase is significantly higher in ICC than in HCC lesions.

Dynamic CT for parathyroid disease: are multiple phases necessary?

A 4D CT protocol for detection of parathyroid lesions involves obtaining unenhanced, arterial, early, and delayed venous phase images. The aim of the study was to determine the ideal combination of phases that would minimize radiation dose without sacrificing diagnostic accuracy. With institutional review board approval, the records of 29 patients with primary hyperparathyroidism who had undergone surgical exploration were reviewed. Four neuroradiologists who were blinded to the surgical outcome reviewed the imaging studies in 5 combinations (unenhanced and arterial phase; unenhanced, arterial, and early venous; all 4 phases; arterial alone; arterial and early venous phases) with an interval of at least 7 days between each review. The accuracy of interpretation in lateralizing an abnormality to the side of the neck (right, left, ectopic) and localizing it to a quadrant in the neck (right or left upper, right or left lower) was evaluated. The lateralization and localization accuracy (90.5% and 91.5%, respectively) of the arterial phase alone was comparable with the other combinations of phases. There was no statistically significant difference among the different combinations of phases in their ability to lateralize or localize adenomas to a quadrant (P = .976 and .996, respectively). Assessment of a small group of patients shows that adequate diagnostic accuracy for parathyroid adenoma localization may be achievable by obtaining arterial phase images alone. If this outcome can be validated prospectively in a larger group of patients, then the radiation dose can potentially be reduced to one-fourth of what would otherwise be administered.

Three-dimensional computerized tomographic angiography for diagnosis and management of intractable postpartum hemorrhage

ObjectiveTo report our experience on the value of dynamic three-dimensional computerized tomographic (CT) angiography for immediate diagnosis and management of intractable postpartum hemorrhage (PPH). Study designRetrospective study of all cases of PPH examined by three-dimensional CT angiography between January 2007 and August 2013 in a single center. In each case, emergency dynamic CT was taken at the early arterial, late arterial and venous phases to identify the extravasated contrast agent that represents active hemorrhage. Images for three-dimensional CT angiography were reconstituted from multiplanar CT images. Based on these findings, management procedures were individually determined and those outcomes were compared with angiographic, surgical and clinical findings. ResultsTwenty-nine cases with primary PPH and 19 cases with secondary PPH were examined. In primary PPH, extravasation in the early arterial phase was noted in 12 cases. Those included vulvovaginal hematoma (n=4), invasive placenta (n=2), retained placenta (n=2), uterine atony (n=1), retroperitoneal hematoma (n=1), retrovesical hematoma (n=1) and rectus sheath hematoma after cesarean section (n=1). Of these, ten cases were treated by transcatheter arterial embolization (TAE) of the offending vessels with or without additional therapies. In secondary PPH, extravasation was identified in 14 cases. Those included invasive placenta (n=8), uterine artery pseudoaneurysm (n=3), uterine arteriovenous fistula (n=2), and subinvolution of placenta bed (n=1), which were treated by TAE of the offending vessels with or without additional therapies. Successful hemostasis with fertility preservation was achieved in all cases. Complications were not identified except for a case of placenta increta that developed secondary amenorrhea after TAE of both uterine arteries. In subsequent gestation after TAE of both uterine arteries, normal vaginal delivery (n=4), uncomplicated cesarean delivery (n=3), cesarean delivery followed by recurrent arteriovenous fistula (n=1) and spontaneous miscarriage followed by recurrent invasive placenta (n=1) were identified. ConclusionsThis case series emphasizes that three-dimensional CT angiography has significant diagnostic value when the appropriate procedure for management of PPH was immediately determined to avoid potential maternal morbidity and mortality.

Contrast-enhanced ultrasound in portal venous system aneurysms: a multi-center study.

To investigate contrast-enhanced ultrasound (CEUS) findings in portal venous system aneurysms (PVSAs). In this multi-center, retrospective, case series study, we evaluated CEUS features of seven cases of PVSAs that were found incidentally on conventional ultrasound in the period 2007-2013. Three Ultrasound Centers were involved (Chieti, Italy, Bad Mergentheim, Germany, and Cluj-Napoca, Romania). All patients underwent CEUS with Sonovue(®) (Bracco, Milan, Italy) at a standard dose of 2.4 mL, followed by 10 mL of 0.9% saline solution. The examinations were performed using multifrequency transducers and low mechanical index. We considered aneurysmal a focal dilatation of the portal venous system with a size that was significantly greater than the remaining segments of the same vein, and that was equal or larger than 21 mm for the extrahepatic segments of portal venous system, main portal vein and bifurcation, and 9 mm for the intrahepatic branches. After contrast agent injection, all PVSAs were not enhanced in the arterial phase (starting 8-22 s). All PVSAs were then rapidly enhanced in the early portal venous phase (starting three to five seconds after the arterial phase, 11-30 s), with persistence and slow washout of the contrast agent in the late phase (starting 120 s). In all patients, CEUS confirmed the presence of a "to-and-fro" flow by showing a swirling pattern within the dilatation in the early portal venous phase. CEUS also improved the delineation of the lumen, and was reliable in showing its patency degree and integrity of walls. In one patient, CEUS showed a partial enhancement of the lumen with a uniformly nonenhancing area in the portal venous and late phases, suggesting thrombosis. In our case series, we found that CEUS could be useful in the assessment and follow-up of a PVSA. Further studies are needed to validate its diagnostic accuracy.

Diagnostic accuracy of 64-MDCT angiography in the preoperative evaluation of renal vessels and compared with laparotomy findings in living donor kidney

Introduction: Multidetector-row computed tomography (MDCT) angiography is a reliable technique in preoperative renal anatomy evaluation in live renal donors. Objectives: To investigate the accuracy of early arterial phase findings and compares them with intraoperative findings. Methods: In this prospective study, 100 potential live donors undergoing preoperative MDCT and nephrectomy during 2010–2013 were included. The examination was performed with a 64-detector scanner including early arterial and venous phase. MDCT angiography started by bolus tracking and venous phase was acquired 9 s after arterial phase. Anatomical findings and vein and artery attenuation values were recorded and arterial phase findings were compared with intraoperative findings. Results: All anatomical findings reported by MDCT in early arterial phase were confirmed by intraoperative findings with sensitivity of 100%. Right renal vein was supernumerary in 17 cases and left renal vein was circumaortic in 3 and retroaortic in 5 cases. Renal arteries had early branching in 13, two arteries in 12 and accessory in 8 cases. Vein and artery attenuation values had significant difference between early arterial and venous phase (p < 0.001). Conclusion: Early arterial phase has similar results to venous phase in preoperative evaluation and intraoperative findings and could be used alone to reduce radiation dose.

Cerebral Proliferative Angiopathy: A Rare Case with Rare Presentation and Rarer Angiographic Features

Introduction Cerebral proliferative angiopathy (CPA) is a distinct entity unlike classical brain arteriovenous malformations (AVMs). Report We describe a patient with seizure who on DSA showed diffuse angiogenesis, absence of a well formed nidus and early venous phase suggestive of fast capillary transit favouring diagnosis of CPA alongwith filling of ophthalmic artery through middle meningeal branch of external carotid artery which made it even rarer. Treatment options are limited and vary with the patient's presentation and angiographic features. Conclusion CPA is rare and filling of ophthalmic artery from middle meningeal artery in association with CPA is even rarer.

A thunderclap headache

The non-contrast CT scan (Fig. 1 of Images in Neuroscience: Question) shows subarachnoid haemorrhage (SAH) within a right frontal lobe sulcus. While the arterial phase image (Fig. 2 of Images in Neuroscience: Question) of the digital subtraction angiography is normal, the early and late venous phase images (Fig. 3a and b of Images in Neuroscience: Question) demonstrate a persistent linear filling defect within the Vein of Trolard confirming thrombus. MRI to assess cerebral parenchyma shows a tubular structure showing high signal on T1-weighted imaging (Fig. 4a of Images in Neuroscience: Question) confined within the pre-central sulcus, indicating thrombus within a vessel or SAH. There is high signal on fluid attenuated inversion recovery MRI and blooming artefact on gradient echo imaging around the previously described tubular structure extending further along the sulcus (Fig. 4b and c of Images in Neuroscience: Question). Together with the CT scan findings and the venogram images, the MRI findings confirm Vein of Trolard thrombosis with adjacent SAH. Thunderclap headache is classically described as severe headache, which takes less than a minute or a few minutes from its onset to peak. The differential diagnosis for thunderclap headache includes SAH, cerebral venous sinus thrombosis, idiopathic benign recurrent headache disorder, arterial dissection, pituitary apoplexy, spontaneous intracranial hypotension, and hypertensive encephalopathy. Cerebral venous thrombosis confined to a cortical vein without involvement of the venous sinuses is rare. In our patient, this was associated with SAH. This phenomenon of SAH secondary to isolated cortical venous thrombosis has been described in a few

Educational Exhibit Abstract No. 337 - Blood pool MRI contrast agent use in pediatric patients for vascular imaging

Learning Objectives We review the imaging technique, discuss advantages/disadvantages, and provide examples of cases where blood pool (BP) contrast MRI may provide new options for pediatric disease detection and monitoring. Background BP contrast agents are a relatively new and promising option in the MR assessment of disease, but currently the experience and published/recognized indications for the use of these agents are limited in the pediatric population. Gadofoveset trisodium (Ablavar) binds reversibly to albumin causing a prolonged BP residence and increasing T1 shortening. Although aortoiliac disease in adults is currently the only FDA-approved indication, other potential applications for BP agents are under investigation. Compared to traditional MRA, BP agents allow for both arterial and venous phase imaging, as well as delayed venous imaging independent of bolus timing. This enables repeat imaging without re-injection, covering a larger anatomic area, e.g. head to foot, if necessary. Clinical Findings/Procedure Details We retrospectively reviewed all MRI studies performed at our institution in children using Ablavar over the past 12 months. After dynamic arterial and early venous phase imaging, delayed venous imaging was performed with high resolution SPGR or MRA imaging with combined respiratory and ECG gating, reconstructed into orthogonal planes. Patient demographic, clinical history, exam indication, MRI technique, and imaging findings as they pertained to dynamic MRA and BP imaging were recorded. The most common indication for utilization of BP contrast agent in our population was for pediatric venography (n=9/22). Other indications included evaluation of liver vessel patency/anatomy (n=7), vasculitis (n=2), acute GI bleeding (n=2), vascular supply of an intra-abdominal mass (n=1), and for refractory hypertension (n=1). Conclusion and/or Teaching Points Blood pool MRI contrast agents can be extremely useful in pediatric imaging for certain indications, particularly for high-resolution venous imaging covering a large area. Optimization of technique and understanding BP imaging benefits/limitations are fundamental to performing an exam with excellent image quality that provides a high degree of diagnostic confidence.

Contrast enhanced magnetic resonance angiography in children: initial experience at 3.0 Tesla

Background To assess the role of contrast enhanced magnetic resonance angiography (CEMRA) at 3.0T in pediatric patients referred for vascular evaluation, and to compare the technical and diagnostic performance of a clinically similar control group at 1.5T. Methods Fifty pediatric patients referred for vascular evaluation and without evidence of congenital heart disease, were evaluated with CEMRA. Thirty-five patients received 37 studies at 3.0T (age 0.4 -16.5 years, mean 5.8 ± 4.7 years. Fifteen patients received 16 studies at 1.5T (age 0.1 - 17.5 years, mean 5.8 ± 6.4 years). CEMRA was performed in three phases: arterial, early venous and late venous. Two independent observers analyzed the studies for image quality, artifacts and vessel definition. Results Overall image quality and vessel definition scores were higher at 3.0T than 1.5T in the arterial and early venous phase, however not the late venous phase. Overall

Peripheral Exudative Hemorrhagic Chorioretinopathy: Polypoidal Choroidal Vasculopathy and Hemodynamic Modifications

To investigate choroidal vascular abnormalities in peripheral exudative hemorrhagic chorioretinopathy, using dynamic ultrawide-field fluorescein angiography (FA) and indocyanine green angiography (ICGA). Prospective observational case series. This institutional study comprised a consecutive series of 40 patients (48 eyes) with peripheral exudative hemorrhagic chorioretinopathy. Choroidal vascular abnormalities were assessed with dynamic ultrawide-field (150-degree) FA and ICGA, using the Staurenghi 230 SLO Retina Lens and the Heidelberg scanning laser ophthalmoscope. The main outcome measures were morphologic descriptions of structural vascular abnormalities and choroidal hemodynamics (comparison with 30 normal eyes). The peripheral mass lesions were highly exudative and hemorrhagic, and usually associated with a pigment epithelium detachment. FA revealed nonspecific alterations corresponding to the visible fundoscopic changes (window defects, blockage, staining), but no neovascular membrane. However, despite frequent masking, ICGA showed hyperfluorescent polyp-like structures in the choroid of the lesion area in 33 eyes (69%) and an abnormal choroidal vascular network in 24 eyes (50%). The abnormal choroidal vascular network filled in the arterial or early venous phase, while the polyp-like structures filled some seconds later. Optical coherence tomography revealed the typical dome-shaped elevation of the pigment epithelium over the vascular polyps. Peripheral choriocapillaris closure was observed as well as dilated shunting vessels. Peripheral exudative hemorrhagic chorioretinopathy shares many characteristics (polyp-like choroidal telangiectases, abnormal choroidal vascular networks, exudative and hemorrhagic presentation) with polypoidal choroidal vasculopathy. Clarification of the precise role of these abnormalities requires further studies.

Bone metastases: Evaluation of acuity of lesions using dynamic gadolinium‐chelate enhancement, preliminary results

To evaluate whether enhancement on serial dynamic gadolinium-enhanced abdominal-pelvic MR imaging (DCE-MRI) can determine the acuity of bone metastases. Twenty consecutive patients who underwent abdominal-pelvic DCE-MRI for evaluation/staging of a proven cancer and had bone metastases were included. Two radiologists analyzed in consensus 59 DCE-MRIs of these patients. Region of interest measurements were performed in up to three lesions on noncontrast T1-weighted, serial hepatic arterial dominant phase (HADP), early hepatic venous phase (EHVF), and interstitial phase (IP) postgadolinium images, and the percentage enhancement of 134 lesions was calculated. The coordinator separately and retrospectively sorted the lesions into three groups based on the imaging and clinical information: acute/active, subacute, and chronic metastases. The mean percentage enhancement of the bone metastases classified as acute/active, subacute, and chronic in the HADP, EHVP and IP were respectively (%): 134, 107, 99; 87, 86, 87; and 39, 65, 73. In the HADP, acute/active lesions enhanced significantly more than both subacute (1.53-fold) and chronic (3.4-fold) lesions (P < 0.01). Time intensity curves were significantly different between these three entities as well. The enhancement on arterial phase images and the time-intensity curves were different for acute/active, subacute, and chronic bone metastases.

Diagnostic value of high spatial and temporal resolution time-resolved MR angiography in the workup of peripheral high-flow vascular malformations at 1.5 Tesla

To evaluate the feasibility and diagnostic impact of time-resolved MR angiography (TR-MRA) combined with parallel imaging and low contrast dose for the assessment of peripheral high-flow vascular malformations (VM) at 1.5 Tesla (T). Twelve consecutive patients (7 female, 5 male, mean age 24.7 ± 11.1 years) with known or suspected high-flow VM underwent time-resolved MRA. Two readers individually assessed image quality, diagnostic confidence as well as hemodynamic features. Digital subtraction angiography (DSA) correlation was available in 9 patients. TR-MRA provided a comprehensive assessment of all VMs with good quality images, allowing reliable differentiation of the early and main arterial phases and of at least the early venous phase. Based on hemodynamic features VM were classified as predominantly arterial malformations in 5 cases (42%), or arteriovenous malformations in the remaining 7 cases (58%). The high-flow component of a VM was confirmed by DSA in 9/9 (100%) cases during the interventional treatment procedure. TR-MRA of peripheral VMs with temporal interpolation and stochastic spiral trajectories is feasible, allowing the assessment of dynamic inflow and vessel-specific information similar to conventional DSA. Therefore, TR-MRA represents a reasonable alternative imaging technique for the pre-treatment evaluation of high-flow VMs.

Quarter-Dose (0.025 mmol/kg) Gadobenate Dimeglumine for Abdominal MRI in Patients at Risk for Nephrogenic Systemic Fibrosis: Preliminary Observations

The purpose of this study is to evaluate the feasibility of 0.025 mmol/kg gadobenate dimeglumine, which is one quarter of the standard dose, for abdominal 3-T MRI studies in patients considered to be at risk for nephrogenic systemic fibrosis, using qualitative and quantitative measures and comparison with higher doses. The MRI database was retrospectively searched to select consecutive patients who underwent quarter-dose gadobenate dimeglumine-enhanced abdominal MRI at 3 T, between January 1, 2009, and January 15, 2010, and who underwent half-dose (0.05 mmol/kg) gadobenate dimeglumine-enhanced abdominal MRI at 3 T during one randomly chosen month. There were 25 patients in the final quarter-dose group (16 men and nine women; mean age, 57 years) and 44 patients in the half-dose group (21 men and 23 women; mean age, 58 years). The enhancement of abdominal organs and aorta was evaluated qualitatively and quantitatively on contrast-enhanced images. The overall quality of abdominal enhancement was also evaluated. Reviewers rated the diagnostic enhancement of the evaluated organs in all phases of enhancement for both studied doses, but the half dose had significantly higher ratings than did the quarter dose in all comparisons (p, 0.034 to < 0.0001), except in the pancreas in the early hepatic venous phase (p = 0.095 for reviewer 1; p = 0.0611 for reviewer 2). The overall enhancement quality of the quarter dose was rated as good in all phases of enhancement, although it was significantly lower than that for the half dose (p ≤ 0.0001). The liver, pancreas, renal cortex, and aorta had 1.52-1.93-fold, 1.53-1.90-fold, 1.46-1.77-fold, and 1.58-1.84-fold, respectively, higher percentages of enhancement with the half dose than with the quarter dose (p, 0.0049 to < 0.0001). A one-quarter dose of gadobenate dimeglumine at 3 T is a feasible alternative for abdominal MRI in patients at risk for nephrogenic systemic fibrosis. Our results might have important clinical implications, because greater safety may be conferred on patients with poor renal function with this low dose of contrast agent.

The Impact of Microscope-Integrated Intraoperative Near-Infrared Indocyanine Green Videoangiography on Surgery of Arteriovenous Malformations and Dural Arteriovenous Fistulae

Microscope-based intraoperative near-infrared indocyanine green (ICG) videoangiography is useful as an adjunct to intra- or postoperative digital subtraction angiography (DSA) in aneurysm surgery. To evaluate intraoperative ICG videoangiography for surgery of arteriovenous malformations (AVMs) and dural arteriovenous fistulas (dAVFs). Seventeen patients undergoing surgical resection of intracranial AVM or AVF were enrolled into this prospective evaluation. ICG videoangiography sequences were analyzed with regard to transit times to differentiate between arterial, early venous, capillary, and venous phase as well as early passage (fistula) and delayed appearance (ischemia). ICG videoangiography was compared with pre- and postoperative angiography. Forty-six ICG videoangiographies were performed in 17 operative procedures. In 41 ICG investigations image quality and spatial resolution were excellent to analyze arterial, early venous, capillary, and venous phase. In 2 cases ICG videoangiography provided additional information to change the surgical strategy. With the exception of one case only, the postoperative angiogram corresponded to the last ICG examination performed after the resection. No side effects related to ICG injection were observed. In one patient with a deep thalamic AVM the final ICG investigation was inconclusive owing to insufficient illumination of the deep surgical field. Microscope-integrated repetitive ICG videoangiography during AVM and dAVF surgery is fast, easy to perform, and safe. This simple and safe real-time method is a useful additional tool that can potentially lower the surgical risk in complex AVMs and help avoid missed residuals.

Evaluation of Relative Wash-In Ratio of Adrenal Lesions at Early Biphasic CT

The purpose of this study was to retrospectively evaluate the accuracy of unenhanced attenuation and relative percentage wash-in ratio in early, that is, arterial and portal venous phase, biphasic CT in differentiating adrenal adenomas from metastatic lesions. One hundred seven adrenal masses in 86 consecutively registered patients (45 men, 41 women; mean age, 56 years) were evaluated. Diagnosis was achieved with percutaneous biopsy (n = 6), surgery (n = 13), and at least 1 year of imaging follow-up (n = 88). Unenhanced, arterial phase, and portal phase scans were obtained. Diameter and absolute attenuation values in each phase of CT were measured in a region of interest covering one to two thirds of a lesion. Relative percentage wash-in ratio was calculated. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in differentiation of adenomas from metastatic lesions were calculated for unenhanced attenuation and for wash-in ratio. A value of p < 0.05 was considered significant. The final diagnosis was metastasis in 51 cases and adenoma in 56 cases. A significant difference was found between benign and malignant lesions in regard to diameter (p = 0.001), unenhanced CT attenuation (p = 0.001), and relative percentage wash-in ratio from the arterial to the portal venous scan (p = 0.014). In the differentiation of benign from malignant lesions, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of unenhanced CT attenuation (at an 11-HU threshold) were 98%, 86%, 86%, 98%, and 92%, and those of relative percentage wash-in ratio from the arterial to the portal venous phase were 94%, 77%, 79%, 93%, and 85%. Relative percentage wash-in ratio may help in differentiating adenoma from metastasis and in guiding the decision to perform CT directed at the adrenal glands when unenhanced CT is not available.

Pancreatic duct changes are not associated with early signs of chronic pancreatitis at magnetic resonance imaging (MRI) in patients with primary sclerosing cholangitis

Objective. The association between chronic pancreatitis (CP) and primary sclerosing cholangitis (PSC) has been reported previously. The aims of the present study were to evaluate the presence of early pancreatic abnormalities and duct changes, using MRCP/MRI in PSC and to evaluate possible risk factors for these changes and their clinical importance. Materials and methods. One hundred and three patients with PSC were identified among all MRI liver/pancreas referrals in 2001–2005. MRCP was used to grade pancreatic duct changes in three groups: grade 0 (normal), grade 1 (mild) and grade 2 (severe). For detection of early MRI signs of CP, the pancreas-spleen signal intensity ratio (SIR), the arterial and early venous phase ratio (A/PV ratio) and the age-related size of the pancreas were evaluated. Results. Pancreatic duct changes were found in 24% of the PSC patients. The pancreatic duct changes were associated with extrahepatic biliary involvement and long duration of PSC but not associated with pancreas-spleen SIR, A/PV ratio, pancreas size, previous post-ERCP or acute pancreatitis. Severe pancreatic duct changes were significantly associated to abdominal pain. Clinically significant CP was seen in one PSC patient (1%). Conclusions. Pancreatic duct changes are associated with extrahepatic bile duct strictures and not with the early MRI signs of CP. Therefore, pancreatic duct changes seem to be part of the spectrum of PSC and should not be defined as CP. Pancreatic duct changes are of limited clinical importance but may contribute to abdominal pain in PSC.