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Monday, December 9, 2019

Correlation of CT Angiography and 99mTechnetium-Labeled Red Blood Cell Scintigraphy to Catheter Angiography for Lower Gastrointestinal Bleeding: A Single-Institution Experience

Clinical Question
Can greater adoption of CT angiography or 99mTechnetium-labeled red blood cell (RBC) scintigraphy reduce the number of nontherapeutic catheter angiography (CA) in the management of lower gastrointestinal bleeding (LGIB)?

Take-away Point
Greater adoption of CT angiography rather than RBC scintigraphy may reduce the number of nontherapeutic CAs given CT’s greater positive correlation to CA and non-increased nephrotoxicity.

Correlation of CT Angiography and 99mTechnetium-Labeled Red Blood Cell Scintigraphy to Catheter Angiography for Lower Gastrointestinal Bleeding: A Single-Institution Experience. Speir, E. J. et al. Journal of Vascular and Interventional Radiology (JVIR), Volume 30, Issue 11, 1725-1732.

Study design
Single-institution, retrospective study of 223 CAs with either pre-procedural CT angiography, RBC scintigraphy, or both for LGIB with laboratory creatinine review 48-72 hours after CA.

Funding Source

No reported funding


Academic hospital, Emory University Hospital, United States of America.

Figure 2.  Positive predictive values of CT angiography (CTA) compared to RBC scintigraphy (NM for nuclear medicine) overall, across clinical variants of LGIB, overall excluding Variant 4 LGIB, and studies completed within 4 hours of CA.


99mTechnetium-labeled red blood cell (RBC) scintigraphy has traditionally served as the initial diagnostic study for imaging evaluation of lower gastrointestinal bleeding (LGIB) given its superior sensitivity. However, frequent subsequent non-therapeutic catheter-based intervention following positive RBC scintigraphy and the advances of CT angiography with superior localization capability have led to the proposal of incorporating CT angiography into the standard management of LGIB. Nonetheless, there was a paucity of literature on the comparative correlations between the two modalities to subsequent catheter angiography. Effects of additional contrast dose on renal function with CT angiography prior to catheter angiography also remained unclear.

The authors performed a retrospective, single institution (3 practicing hospitals) of 223 cases (unique patient count of 207) of catheter angiography for evaluation of LGIB with pre-procedural CT angiography, RBC scintigraphy, or both. Catheter angiography was used as the reference standard. All 4 variants of LGIB were included and were used for sub-analysis. Exclusion criteria included no CT angiography or RBC scintigraphy within 30 hours of catheter angiography, prophylactic embolization, provocative catheter angiography, and inadequate pre-procedural imaging or procedural evaluation.

Out of the 223 cases of catheter angiography, 38 had CT angiography, 173 had RBC scintigraphy, and 12 had both types of pre-procedural imaging. The authors found CT angiography had a higher positive correlation of 67.7% with catheter angiography, compared to 29.3% of RBC scintigraphy. This difference was more dramatic if the pre-procedural imaging were completed within 4 hours preceding catheter angiography. Interestingly, positive correlation of RBC scintigraphy with catheter angiography was reported to be 75.0% when performed within 1 hour of catheter angiography. No significant dose-toxicity relationship between contrast and renal function was found. No significant differences of CIN incidence was found between the two arms.


The authors in this study have demonstrated greater positive correlation of CT angiography with catheter angiography compared to RBC scintigraphy for assessing LGIB. Furthermore, they have showed non-increased nephrotoxicity associated with the additional contrast dose when CT angiography was utilized prior to catheter angiography. This study, with its retrospective nature and unequal CT angiography versus RBC scintigraphy case proportions, had its inherent limitations. Clinicians and proceduralists would have skewed towards proceeding with catheter angiography or not given the known high negative predictive value of CT angiography and high sensitivity of RBC scintigraphy. Therefore, future prospective randomized clinical trials may be necessary to definitely answer the question. The timing aspect, however, should not be understated. Dramatically increased positive correlations to catheter angiography were observed with shorter positive pre-procedural imaging to catheter angiography time regardless of the imaging choice. This highlighted the importance of prompt transitioning from pre-procedural imaging to catheter-based intervention which should be an important focus of a standardized LGIB management protocol.

Post Author
Ningcheng (Peter) Li, MD, MS
Integrated Interventional Radiology Resident, PGY-3
Department of Interventional Radiology
Oregon Health and Science University, Dotter Interventional Institute


Friday, December 6, 2019

Uterine Artery Embolization with Gelfoam for Acquired Symptomatic Uterine Arteriovenous Shunting

Clinical Question
To evaluate the technical and clinical success rates and safety of bilateral gelfoam uterine artery embolization (UAE) for symptomatic acquired uterine arteriovenous shunting due to prior obstetric or gynecologic event.

Take-away Point
Gelfoam embolization of bilateral uterine arteries is effective in treating abnormal uterine bleeding secondary to AV shunting caused by gynecologic or obstetric intervention and allowed for future pregnancy.


Camacho A, Ahn E, Appel E, Boos J, Nguyen Q, Justaniah A, Faintuch S, Ahmed M, Brook O. (2019). Uterine Artery Embolization with Gelfoam for Acquired Symptomatic Uterine Arteriovenous Shunting. J Vasc Interv Rad, 30:1750-1758. doi:10.1016/j.jvir.2019.04.002

Click here for abstract:

Study Design
Retrospective single center study

Funding Source

Dept of Radiology, Beth Isreal Deaconess Medical Center; Department of Diagnostic and Interventional Radiology, University Dusseldorf

Figure 3. A 39-year-old G1P1 with continued heavy bleeding after cesarean delivery concerning on ultrasound for arteriovenous shunting, (a) Left uterine arteriogram shows a large-caliber shunt into the left internal iliac vein. (b) Gelfoam alone was insufficient to close the shunt. (c) Coils were used to complete the occlusion.


A retrospective review from Jan 2013 – Feb 2018 was performed at a tertiary referral center for gelfoam UAE’s performed for abnormal uterine bleeding after recent gynecologic procedure or obstetric event. All patients had suspected or known uterine AV shunting based on pre-procedural imaging with ultrasound +/- MRI. 18 patients who underwent 19 UAEs were evaluated. Average peak systolic velocity on ultrasound was 59.8 ± 40.9 cm/s with RI of 0.45 ± 0.13. Technical success was angiographic resolution of the AV shunting and clinical success was defined as cessation of bleeding, resolution on imaging or <50 cc blood loss on subsequent D&C.

The technical success rate of UAE with gelfoam was 94.4% with one patient requiring additional coil embolization due to the large size of the shunt. A second angiogram was performed on a single patient with pelvic US demonstrating persistent but diminished shunting however no shunt was identified and repeat embolization was not performed. Clinical success rate was 94.1% in the 17 successful UAEs. One minor complication – groin hematoma – and one major complication – pulmonary embolism – occurred in the patient group. Clinical improvement was noted in all patients on follow-up. Seven patients had subsequent pregnancies without placenta accrete although there was one patient with placenta previa.


Treatment of abnormal uterine bleeding secondary to gynecological or obstetric intervention can be treated successfully with UAE with a high clinical and technical success rate as demonstrated in this study as well as several others by Wang et al, Ganguli et al and Ghai et al for example. Treatment with gelfoam slurry as opposed to coils, particles or gelfoam pledgets may confer a higher success rate as described by the authors while allowing for increased fertility. Further study is needed to truly assess the post-UAE fertility rate as this was a secondary endpoint and confounded by miscarriages and unplanned terminated pregnancies. Additional study may also define which particle is ideal for preserved fertility as particles are frequently used in the setting of fibroid embolization.

Post Author
Nicole A. Keefe, MD
Fellow, Interventional Radiology
Department of Radiology and Medical Imaging
University of Virginia


Monday, December 2, 2019

Balloon Guide Catheter in Endovascular Treatment for Acute Ischemic Stroke: Results from the MR CLEAN Registry


Clinical question
Compare the outcomes after endovascular treatment for acute ischemic stroke with and without the use of a balloon guide catheter.

Take away point
Balloon guided catheters are associated with higher reperfusion grade, early improvement in neurologic status, and lower rates of symptomatic ICH. However their use has no positive effect on long-term functional outcome.

Goldhoorn, Robert-Jan B., et al. Balloon Guide Catheter in Endovascular Treatment for Acute Ischemic Stroke: Results from the MR CLEAN Registry. Journal of Vascular and Interventional Radiology, Volume 30, Issue 11, 1759-64

Click here for abstract

Study design

Retrospective review of data collected during the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in The Netherlands (MR CLEAN).

Funding source

Medical centers participating in the MR CLEAN trial in the Netherlands.

Figure 2.
Functional outcome on the mRS (modified Rankin Score) for patients treated with BGC (balloon guide catheter) vs non-BCG for acute ischemic stroke intervention.


Endovascular treatment of acute ischemic stroke has been shown to improve patient outcomes. Multiple endovascular methods have been developed to remove the acute thrombus from the occluded vessel. Currently it is operator depending on the technique used to re-vascularize the ischemic segment of tissue. These include mechanical clot disruption (stent retriever) with and without flow arrest, aspiration thrombectomy, local thrombolytic infusion and a combination of these techniques. Flow arrest is obtained by using a balloon guide catheter or in cases of high grade carotid stenosis it occurs when a sheath is placed across the stenotic lesions. The authors used data from the MR CLEAN trial and compared patients long-term functional outcome, eTICI score (reperfusion grade) and HIHSS score 24-48 hours after intervention.

All the patients were part of a randomized control trial and underwent endovascular treatment for acute ischemic stroke. Balloon guide catheters (BGC) were used in 538 patients (60%) and 359 patients (40%) had intervention without BGC. The individual operator technique was not discussed in this paper since it was looking at data from a RCT, which had numerous operators throughout the Netherlands.

The primary outcome was modified Rankin Scale (mRS) score at 90 days. The secondary outcomes were reperfusion grade after treatment (eTICI) and National Institutes of Health Stroke Scale (NIHSS) score after 24-48 hours.

The use of logistic regression was used to adjust for age, sex, prestrike mRS score, NIHSS score, collateral grade, and time from onset to EVT.

The percentage of functionally independent patients at 90 days was similar between the 2 groups (41% vs 39%; P- 0.64). BGC significantly improved eTICI (acOR, 1.33; 95% CI, 1.04-1.70) and reperfusion (eTICI grade =/> 2B) in the BGC group (75%) vs the non-BGC group (68%) with a P = 0.02. NIHSS score was lower in patients treated with BGC (9 vs 11, P – 0.06) with an improvement of 4+ points more frequently (62% vs 52%; P < 0.01). After adjusting for confounders the use of BGC had a decreased death rate (23% vs 29%, P = 0.03).


The authors retrospectively evaluated data from a national RCT for acute ischemic stroke to see if the use of balloon guide catheters (BGC) had a better outcome. They found that there was no difference in 90 day functional outcome of patients when comparing the two endovascular techniques. They did find that patients who had endovascular revascularization with a BGC had better early improvement in NIHSS scores and better reperfusion grades (eTICI).

It is very difficult to directly apply the study results to daily stroke practice. The use of BGC didn’t improve 90 day functional outcome; however it did result in early patient improvement. I think it would be interesting to study how this effects resource utilization. Patients that improve quickly after a stroke can be stepped down to a lower level of care and return home earlier, which may benefit their overall well-being and decrease hospital cost. I don’t think this will result in decreased utilization of balloon guide catheters in stroke treatment; however, further studies need to be done to confirm or disprove these findings.

Post Author
Hasnain Hasham, MD
Interventional Radiology Fellow
Dotter Interventional Institute
Oregon Health and Science University, Portland, OR