Long term impact of transjugular intrahepatic portosystemic shunt (TIPS) creation on hepatic morphology.

PURPOSE: The purpose of this study was to evaluate long-term morphologic changes occurring in the liver after TIPS creation with correlation with hepatic function to gain insight on the physiologic impact of TIPS on the liver. METHODS: This retrospective study included patients who underwent TIPS creation between 2005 and 2022 and had contrasted CT or MRI studies prior to and between 1 and 2 years post procedure. Strict exclusion criteria were applied to avoid confounding. Parenchymal volume and vessel measurements were assessed on the pre- and post-TIPS CT or MRI and MELD scores calculated. RESULTS: Of 580 patients undergoing TIPS creation, 65 patients (mean age, 55 years; 36 males) had pre-TIPS and post-TIPS imaging meeting inclusion criteria at median 16.5 months. After TIPS, the mean MELD score increased (12.9 to 15.4; p = 0.008) and total liver volume decreased (1730 to 1432 mL; p < 0.001). However, the magnitude of volume change did not correlate with MELD change. Neither portosystemic gradient nor TIPS laterality correlated with total or lobar hepatic volume changes or MELD changes. The main portal vein diameter increased (15.0 to 18.7 mm; p < 0.001). Thrombosis of the hepatic vein used for TIPS creation resulted in a mean increase in MELD of +4.1 compared to -2.1 in patients who had a patent and normal hepatic vein (p = 0.007). CONCLUSIONS: Given lack of correlation between portosystemic gradient, hepatic atrophy, hepatic function, and TIPS laterality, the alterations in portal flow dynamics after TIPS may not be impactful to hepatic function. However, hepatic vein patency after TIPS correlated with improved hepatic function.

Comparing magnetic resonance imaging and ultrasound in the clinical evaluation of fibroids prior to uterine artery embolization.

PURPOSE: Uterine artery embolization has become established as a frontline treatment for uterine leiomyomata. In planning embolization, preprocedural imaging can further characterize pathology and anatomy, but it may also reveal coexisting diagnoses that have the potential to change clinical management. The purpose of this study is to compare the diagnostic outcomes of ultrasound and MRI performed for patients prior to undergoing embolization. METHODS: The study cohort consisted of 199 patients who underwent uterine artery embolization at a single academic institution between 2013 and 2018. Prior to embolization, all patients had an MRI confirming a leiomyomata diagnosis. Additionally, 118 patients underwent transvaginal ultrasound within five years prior to MRI. MRI findings were analyzed and, when applicable, compared to prior ultrasound impressions to assess for the incidence of new findings. The diagnoses of interest were adenomyosis, hydrosalpinx, predominantly infarcted leiomyomata, and large intracavitary leiomyomata. Data were collected from retrospective chart review and included demographics, symptomology, and imaging reports. RESULTS: 199 patients ultimately underwent embolization for treatment of MRI-confirmed leiomyomata. Of 118 patients who also had an ultrasound within five years prior to their MRI, 26 (22.0%) received a second gynecologic diagnosis based on MRI findings that was not previously seen on ultrasound. Of 81 patients who only had an MRI before embolization, 19 (23.5%) received a second gynecologic diagnosis not previously documented. The most common coexisting pathology was adenomyosis, presenting in 34 (17.1%) patients with leiomyomata, followed by large intracavitary leiomyomata (8, 4.0%), infarcted leiomyomata (7, 3.5%), and hydrosalpinx (6, 3.0%),. CONCLUSIONS: When considering uterine artery embolization for the treatment of symptomatic leiomyomata, preprocedural MRI is superior to ultrasound in detecting coexisting pathologies, including adenomyosis and hydrosalpinx. It can also better characterize leiomyomata, including identifying lesions as intracavitary or infarcted. These findings have the potential to alter clinical management or contraindicate embolization entirely.

Intravascular Ultrasound Guidance for Transjugular Intrahepatic Portosystemic Shunt Creation Reduces Laboratory Markers of Acute Liver Injury.

PURPOSE: To compare the laboratory markers of acute liver injury after transjugular intrahepatic portosystemic shunt (TIPS) creation performed using intravascular ultrasound (IVUS) guidance with those using other techniques. MATERIALS AND METHODS: This single-center, retrospective study examined 293 TIPS procedures performed between 2014 and 2022 (160 men; mean age, 57.4 years; 71.7% with ascites, 158 with IVUS). Laboratory changes on postprocedural day (PPD) 1 were classified based on Common Terminology Criteria for Adverse Events (CTCAE) grades and were compared between IVUS and non-IVUS cases. RESULTS: IVUS cases had a lower baseline Model for End-Stage Liver Disease (MELD) score (12.5 vs 13.7, P = .016), higher pre- (16.8 vs 15.2, P = .009), and post-TIPS (6.6 vs 5.4 mm Hg, P < .001) pressure gradient, smaller stent diameter (9.2 vs 9.9 mm, P < .001), and fewer needle passes (2.4 vs 4.2, P < .001). IVUS predicted a lower PPD 1 CTCAE grade for aspartate transaminase (8.0% vs 22.2% grade ≥ 2, P = .010), alanine transaminase (ALT) (2.2% vs 7.1%, P = .017), and bilirubin (9.4% vs 26.2%, P < .001), findings confirmed using multivariable regression and propensity score analysis. IVUS predicted fewer adverse events (1.3% vs 8.1%, P = .008) and an increased likelihood of PPD 1 discharge (81% vs 59%, P = .004). IVUS was not associated with differences in PPD 30 MELD scores or 30-day survival; however, higher PPD 1 ALT (ß = 1.96, P = .008) and bilirubin levels (ß = 1.38, P = .004) predicted larger PPD 30 MELD score increase. Higher increases in ALT level predicted worse 30-day survival (hazard ratio, 1.93; P = .021). CONCLUSION: IVUS resulted in less laboratory evidence of acute liver injury immediately following TIPS creation.

Intravascular Ultrasound-Guided Transvenous Biopsy of Retroperitoneal Lymph Nodes: Diagnostic Accuracy and Safety Compared with CT-Guided Percutaneous Biopsy.

PURPOSE: To compare the diagnostic accuracy and adverse event rates of intravascular ultrasound (US)-guided transvenous biopsy (TVB) versus those of computed tomography (CT)-guided percutaneous needle biopsy (PNB) for retroperitoneal (RP) lymph nodes. MATERIALS AND METHODS: In this single-institution, retrospective study, 32 intravascular US-guided TVB procedures and a sample of 34 CT-guided PNB procedures for RP lymph nodes where targets were deemed amenable to intravascular US-guided TVB were analyzed. Procedural metrics, including diagnostic accuracy, defined as diagnostic of malignancy or a clinically verifiable benign result, and adverse event rates were compared. RESULTS: The targets of intravascular US-guided TVB were primarily aortocaval (47%, 15/32) or precaval (34%, 11/32), whereas those of CT-guided PNB were primarily right pericaval (44%, 15/34) or retrocaval (44%, 15/34) (P < .001). The targets of intravascular US-guided TVB averaged 2.4 cm in the long axis (range, 1.3-3.7 cm) compared with 2.9 cm (range, 1.4-5.7 cm) for those of CT-guided PNB (P = .02). There was no difference in the average number of needle passes (3.8 for intravascular US-guided TVB vs 3.9 for CT-guided PNB; P = .68). The diagnostic accuracy was 94% (30/32) and the adverse event rate was 3.1% (1/32) for intravascular US-guided TVB, similar to those of CT-guided PNB (accuracy, 91% [31/34]; adverse event rate, 2.9% [1/34]). CONCLUSIONS: Intravascular US-guided TVB had a diagnostic accuracy and adverse event rate similar to CT-guided PNB for RP lymph nodes, indicating that intravascular US-guided TVB may be as safe and effective as conventional biopsy approaches for appropriately selected targets.

Utility of CBCT and AVD for intraprocedural diagnosis and treatment of lower GI bleeding.

BACKGROUND: Intraprocedural Cone Beam CT (CBCT) is assessed to examine if use improves diagnosis and embolization rates of acute lower GI bleed (LGIB) and if automatic vessel detection (AVD) software can identify feeding vessels (FV) for embolization. METHODS: Patients with inconclusive DSA findings had CBCT and retrospective analysis with AVD software (Innova 3100, GE Company, USA). Technical success was defined as the ability to detect a lower GIB site while clinical success was defined as successful embolization without evidence of rebleeding or death within 30 days. AVD technical success was defined by the ability to identify the FV on both CTA and CBCT upon independent review by 3 blinded IRs, who also assigned a degree of certainty on a 5-point Likert scale. RESULTS: 74 patients in total were treated for lower GI bleed of which 34 had indeterminate DSA. Of those, 10 patients received DSA only, of which 1 was super selective. 24 patients with GIB on pre-procedural CTA and inconclusive DSA underwent CBCT. Use of CBCT identified 9 bleeds not seen on DSA and an additional source artery in 1 case representing a 42% change in intraprocedural management as all findings were embolized. When a bleed could not be identified on CBCT, but the FV could be identified on CTA, the same suspected FV could be selected on AVD 62% of the time with an average certainty of 4.0. CONCLUSION: CBCT is useful in the intraprocedural detection of GIB when DSA is indeterminate. Furthermore, AVD software can feasibly be utilized to accurately identify FVs for empiric treatment when intraprocedural imaging is inconclusive. LEVEL OF EVIDENCE: Level III, therapeutic study.

Patient Radiation Doses in IR Procedures: The American College of Radiology Dose Index Registry-Fluoroscopy Pilot.

PURPOSE: To update normative data on fluoroscopy dose indices in the United States for the first time since the Radiation Doses in Interventional Radiology study in the late 1990s. MATERIALS AND METHODS: The Dose Index Registry-Fluoroscopy pilot study collected data from March 2018 through December 2019, with 50 fluoroscopes from 10 sites submitting data. Primary radiation dose indices including fluoroscopy time (FT), cumulative air kerma (Ka,r), and kerma area product (PKA) were collected for interventional radiology fluoroscopically guided interventional (FGI) procedures. Clinical facility procedure names were mapped to the American College of Radiology (ACR) common procedure lexicon. Distribution parameters including the 10th, 25th, 50th, 75th, 95th, and 99th percentiles were computed. RESULTS: Dose indices were collected for 70,377 FGI procedures, with 50,501 ultimately eligible for analysis. Distribution parameters are reported for 100 ACR Common IDs. FT in minutes, Ka,r in mGy, and PKA in Gy-cm2 are reported in this study as (n; median) for select ACR Common IDs: inferior vena cava filter insertion (1,726; FT: 2.9; Ka,r: 55.8; PKA: 14.19); inferior vena cava filter removal (464; FT: 5.7; Ka,r: 178.6; PKA: 34.73); nephrostomy placement (2,037; FT: 4.1; Ka,r: 39.2; PKA: 6.61); percutaneous biliary drainage (952; FT: 12.4; Ka,r: 160.5; PKA: 21.32); gastrostomy placement (1,643; FT: 3.2; Ka,r: 29.1; PKA: 7.29); and transjugular intrahepatic portosystemic shunt placement (327; FT: 34.8; Ka,r: 813.0; PKA: 181.47). CONCLUSIONS: The ACR DIR-Fluoro pilot has provided state-of-the-practice statistics for radiation dose indices from IR FGI procedures. These data can be used to prioritize procedures for radiation optimization, as demonstrated in this work.

Patient Radiation Doses in Interventional Radiology Procedures: Comparison of Fluoroscopy Dose Indices between the American College of Radiology Dose Index Registry-Fluoroscopy Pilot and the Radiation Doses in Interventional Radiology Study.

PURPOSE: To compare radiation dose index distributions for fluoroscopically guided interventions in interventional radiology from the American College of Radiology (ACR) Fluoroscopy Dose Index Registry (DIR-Fluoro) pilot to those from the Radiation Doses in Interventional Radiology (RAD-IR) study. MATERIALS AND METHODS: Individual and grouped ACR Common identification numbers (procedure types) from the DIR-Fluoro pilot were matched to procedure types in the RAD-IR study. Fifteen comparisons were made. Distribution parameters, including the 10th, 25th, 50th, 75th, and 95th percentiles, were compared for fluoroscopy time (FT), cumulative air kerma (Ka,r), and kerma area product (PKA). Two derived indices were computed using median dose indices. The procedure-averaged reference air kerma rate (Ka,r¯) was computed as Ka,r / FT. The procedure-averaged x-ray field size at the reference point (Ar) was computed as PKA / (Ka,r × 1,000). RESULTS: The median FT was equally likely to be higher or lower in the DIR-Fluoro pilot as it was in the RAD-IR study, whereas the maximum FT was almost twice as likely to be higher in the DIR-Fluoro pilot than it was in the RAD-IR study. The median Ka,r was lower in the DIR-Fluoro pilot for all procedures, as was median PKA. The maximum Ka,r and PKA were more often higher in the DIR-Fluoro pilot than in the RAD-IR study. Ka,r¯ followed the same pattern as Ka,r, whereas Ar was often greater in DIR-Fluoro. CONCLUSIONS: The median dose indices have decreased since the RAD-IR study. The typical Ka,r rates are lower, a result of the use of lower default dose rates. However, opportunities for quality improvement exist, including renewed focus on tight collimation of the imaging field of view.

Coaxial Stent Graft inside a Constraining Stent for Transjugular Intrahepatic Portosystemic Shunt Reduction.

A technique to create a coaxial, self-expanding stent graft inside a constraining, bare-metal, balloon-expandable stent for transjugular intrahepatic portosystemic shunt (TIPS) reduction is described. The key steps are performed on a back table rather than inside the patient, and the resulting construct is deployed using standard unsheathing maneuvers. The construct was used in 4 patients to make 6 TIPS diameter reductions (mean postreduction diameter, 6 mm; range, 0-8 mm), all resulting in increases in the portosystemic pressure gradient (mean increase, 6 mm Hg; range, 1-19 mm Hg). On average, hepatic encephalopathy improved 1 point on the West Haven scale (range, 0-2).

Diagnostic accuracy of clinically reported adenomyosis on pelvic ultrasound and MRI compared to surgical pathology.

BACKGROUND: Adenomyosis is a common gynecologic pathology that relies on diagnostic imaging to guide treatment. Accuracy of both pelvic ultrasound and magnetic resonance imaging (MRI) when specifically evaluating for the presence of adenomyosis is high. However, the accuracy of reported rates in clinical practice is less well understood. PURPOSE: To demonstrate the accuracy in reporting of adenomyosis on pelvic ultrasound and MRI compared to histopathology in common clinical practice. BASIC PROCEDURES: An institutional database was searched for women with a pelvic ultrasound and a pelvic MRI with a subsequent hysterectomy. Findings were extracted from radiology and pathology reports, and the documented presence or absence of adenomyosis was recorded for each modality. Blinded radiologists viewed each imaging pair to directly evaluate for adenomyosis. MAIN FINDINGS: Compared to prior published data, imaging had lower accuracy in clinical practice when adenomyosis was not specifically evaluated for. For the finding of adenomyosis, pelvic ultrasound had a sensitivity of 10.9%, a specificity of 98.3%, positive predictive value (PPV) of 77.8%, negative predictive value (NPV) of 66.7%, an accuracy of 67.2%, and a diagnostic odds ratio (DOR) of 7. Pelvic MRI had a sensitivity of 29.7%, specificity of 85.3%, PPV of 52.8%, NPV of 68.8%, an accuracy of 65.6%, and DOR of 2.5. Overall accuracy of MRI improved when adenomyosis was directly evaluated for (82.4% vs 65.6%). PRINCIPLE CONCLUSIONS: Without direct communication to evaluate for adenomyosis, pelvic ultrasound and MRI may underestimate or misreport adenomyosis. Providers should be aware of these discrepancies when relying on radiology reports to guide treatment and potential interventions when diagnosing and managing adenomyosis.

Hemodialysis Reliable Outflow (HeRO) graft creation in upper extremities abandoned due to stent obstruction via recanalization and HeRO outflow component insertion across stent interstices.

BACKGROUND: The purpose of this study was to assess the feasibility and outcomes of recanalization and subsequent HeRO graft outflow component insertion across stent interstices in patients with an otherwise abandoned upper extremity. METHODS: Over a 10-year period, 15 patients underwent central venous recanalization by interventional radiology across the interstices of one or more occluded stents for the purpose of subsequent HeRO graft creation. A tunneled central venous catheter was left across the stent and occlusions with tip in right atrium. On a later date, the catheter was used for rapid guidewire access for HeRO graft implantation in the OR by vascular surgery. Procedural and clinical outcomes were determined by retrospective review. Primary and secondary HeRO graft patency rates were estimated with the Kaplan-Meier technique. RESULTS: The technical success rates of recanalization across stent interstices was 100% (15/15). Between one and four overlapping stent walls were traversed. The technical success of the patients who underwent attempted HeRO graft implantation with outflow component traversing across stent interstices was 91% (11/12). No major complications were encountered with either recanalization or HeRO graft implantation. The primary and secondary HeRO patency rates at 12 months were 64% and 80%, respectively. CONCLUSION: HeRO graft insertion across stent interstices is feasible and can provide effective permanent AV access; thus, the presence of stents across the subclavian and brachiocephalic veins should not be considered a contraindication.

Treatment of Arm Swelling in Hemodialysis Patients with Ipsilateral Arteriovenous Access and Central Vein Stenosis: Conversion to the Hemodialysis Reliable Outflow Graft versus Stent Deployment.

PURPOSE: To compare outcomes after conversion of arteriovenous (AV) access to Hemodialysis Reliable Outflow (HeRO) graft vs stent deployment in patients with arm swelling owing to ipsilateral central vein stenosis. MATERIALS AND METHODS: This single-center retrospective study comprised 48 patients (19 men, mean age 58 y) with arm swelling ipsilateral to AV access and central vein stenosis over a 13-year period who had clinical follow-up and without prior central stents. Twenty-one patients underwent placement of a HeRO graft with anastomosis of the HeRO graft to the existing graft or fistula, and 27 patients underwent central venous stent deployment. Symptomatic improvement in arm swelling and access patency rates after intervention were ascertained from medical records. RESULTS: Improvement in swelling within 1 month after HeRO conversion and stent deployment was found in 95% and 89%, respectively (P = .62). Swelling eventually recurred in 16 patients (59%) treated with stents compared with 1 patient (5%) who underwent HeRO conversion (P < .001). Primary access patency was statistically significantly longer after HeRO conversions than stent deployments, with 6- and 12-month primary patency rates of 89% and 72% vs 47% and 11% (P < .001). HeRO conversions also resulted in longer 6- and 12-month secondary access patency rates (95% and 95% vs 79% and 58%, P = .006). Mean number of interventions per 1,000 access days to maintain secondary patency was 2.7 for the HeRO group vs 6.3 for the stent group. CONCLUSIONS: Although stent deployment and HeRO graft conversion are effective for alleviating arm swelling in the short term in patients receiving hemodialysis with clinically significant arm swelling and functioning AV access, the HeRO graft has more durable results.

Uterine artery embolisation for IVC syndrome and severe lower extremity oedema secondary to IVC compression from massive fibroids.

A 66-year-old woman was admitted to an outside facility with leg swelling and dyspnea on exertion. Initial workup revealed severe aortic stenosis and congestive heart failure (CHF) thought to be the culprit; however, a CT performed in the emergency department revealed massive uterine mass resulting in significant inferior vena cava (IVC) compression. Her cardiac status precluded hysterectomy, due to concerns regarding intraoperative fluid shifts decreasing preload in the setting of preload dependence in severe aortic stenosis. Similarly, her degree of IVC compression was thought to make valve replacement unacceptably dangerous, so she was referred to interventional radiology for consideration of uterine artery embolisation (UAE) to relieve IVC compression. She underwent UAE without complication, and her leg swelling nearly completely resolved at follow-up.

Evaluating Resident On-Call Performance: Does Volume Affect Discrepancy Rate?

OBJECTIVE: To examinehow study volume affects discrepancy rates for on-call radiology residents. Inparticular, we studied how both total shift volume and volume at a particularpoint in time might effect performance. MATERIALS/METHODS: Weretrospectively analyzed 518 weekend call shifts at our institution. The totalnumber of computed tomography (CT) studies per shift was recorded. For everyabdomen-pelvis (AP) or chest-abdomen-pelvis (CAP) CT, preliminary and finalreports were compared for possible discrepancy and rated (by effect on short-termmanagement). We also developed "peristudy volume," defined as CTs read within ±30minutes of a given CT, an estimate of how busy a resident might be at a giventime. We performed logistic regressions to determine whether overall shiftvolume or peristudy volume were predictors of discrepancies. RESULTS: CTvolume/day increased from 58.1 ± 10.1 in 2011 to 75.3 ± 12.5 in 2015(p<0.001). 4695 AP (or CAP) CTs were reviewed, with 145 discrepancies thatcould affect short-term management (3.1%). When reading a study during a shift with≥51 total CTs,residents had increased odds of an error compared to reading a study during ashift with ≤30 studies (OR: 2.97, CI: 1.19-6.46) (p=0.01). When reading a CTwith a peristudy volume of ≥6, residents had increased odds of an error comparedto reading a study with ≤5 peristudy CTs (OR: 1.6, CI: 1.1-2.3) (p=0.01). CONCLUSION: Whenon-call residents interpret AP CT during high volume shiftsor during busy time-points, odds of discrepancies increase. Awareness of thesedata may inform residency programs in staffing decisions.

MR Venography of the Central Veins of the Thorax.

While imaging of the central venous system has traditionally been performed with conventional venography, MR venography (MRV) has emerged as an important modality as techniques and validation studies have evolved over time. While magnetic resonance angiography has a very robust representation in the literature, the proportion representing MRV is relatively sparse. The purpose of this article is to review the indications, techniques, and dedicated studies validating MRV of the central veins of the thorax.

Intravenous thrombolysis outcomes in patients presenting with large vessel acute ischemic strokes--CT angiography-based prognosis.

BACKGROUND AND PURPOSE: To establish outcome rates for patients receiving intravenous thrombolysis based on vascular occlusion site. METHODS: This is a retrospective analysis of 225 patients who had received intravenous-rt-PA for anterior circulation strokes. The occlusion-site was prospectively determined on the admission computed tomographic angiography (CTA) and divided into: large vessel occlusion (LVO) including patients with an internal carotid artery terminus or middle cerebral artery (M1/proximal M2) occlusions and no large vessel occlusion (No-LVO; distal M2/M3/ACA) including patients with either distal or no occlusions. The primary outcome was the modified Rankin score (mRS) at 90-days with a good outcome defined by mRS of 0-2.000. RESULTS: There were 114 (50.7%) patients in the LVO and 111 (49.3%) in the No-LVO group. A good outcome was seen in 28 (24.6%) patients in the LVO and 77 (69.4%) patients in the No-LVO group (OR .14; 95% CI: .08-.26; P < .0001). Mortality was observed in 13 (11.7%) patients in the No-LVO group and 48 (42.1%) patients in the LVO group (OR .18; 95% CI: .09-.36; P < .0001). Significant hemorrhage was seen in 14 (12.5%) patients in the LVO and 0 (0%) patients in the No-LVO group (P < .0001). Older age (OR .96; 95% CI: .93-.98; P = .002) and presence of LVO (OR .29; 95% CI: .12-.68; P = .004) were significant independent predictors of poor outcome. CONCLUSION: CTA identification of proximal occlusions is associated with significantly poor outcomes in patients receiving intravenous stroke thrombolysis.

Cerebrovascular geometry in the anterior circulation: an analysis of diameter, length and the vessel taper.

BACKGROUND: A study was undertaken to determine the typical length, diameter and taper of vessels in the anterior cerebral circulation. METHODS: The sample size was calculated at 100 patients based on similar measurements in the literature and divided into cohorts based on gender and side. These patients were consecutively collected from a population that had undergone CT angiography and did not have any vascular abnormality. The arterial diameter was measured at the proximal cavernous internal carotid artery (ICA), the ICA terminus, the middle cerebral artery (MCA) origin and an M2 origin. The length between these endpoints was calculated along the center line. The vessel taper was calculated for the ICA as the change in caliber per unit length. RESULTS: The mean length of the ICA from the proximal cavernous segment to the ICA terminus was 33.1 ± 6.1 mm. The mean diameter at the cavernous ICA and the ICA terminus was 5 ± 0.6 mm and 3.6 ± 0.4 mm, respectively. The mean ICA taper was 0.04 ± 0.02 mm/1 mm. For the MCA, the diameter at the MCA and M2 origins measured 3.1 ± 0.4 mm and 2.4 ± 0.4 mm, respectively. The mean MCA length was 22.5 ± 8.1 mm. There was no significant difference based on gender or between right and left sides. Patients aged >60 years had longer ICAs (p=0.02), larger cavernous ICA (p=0.003), ICA terminus (p<0.0001) and MCA origin (p=0.01) diameters than those aged 40-60 years. The ICA vessel taper did not change with age. CONCLUSION: ICA and MCA vessel size did not change based on gender or side. Older patients had more redundant vessels based on diameter and length. The ICA has a gentle taper from its proximal cavernous segment to the ICA terminus. This information can be important in planning interventions or designing endovascular devices.