Photon-counting detector CT with an ultra-low-dose contrast media to diagnose a renal pseudoaneurysm: A case report.

A 75-year-old male, weighing 71 kg, was admitted to our institution with anemia related to a subcapsular hematoma after accidental extraction of a nephrostomy catheter. While the patient exhibited the progression of chronic kidney disease, he was not yet on dialysis. His serum creatinine level increased to 6.8 mg/dL, with an estimated glomerular filtration rate of 7.4 mL/min/1.73 m2. Radiologists planned contrast-enhanced photon-counting detector CT (PCD-CT) with an ultra-low-dose contrast media to mitigate the impact on renal function. The contrast media dosage was set at 7.4 gI, which was 82.6% lower that used in the standard protocol for a male weighing 71 kg. Non-contrast-enhanced PCD-CT identified a low-density nodular area within the renal subcapsular hematoma. Contrast-enhanced PCD-CT revealed contrast enhancement in both the early and late phases corresponding to the nodular area. On virtual monoenergetic images, the renal pseudoaneurysm was most clearly delineated at 40 keV. Following the diagnosis of a pseudoaneurysm, transcatheter arterial coil embolization was performed. No subsequent progression of anemia or the deterioration of renal function was observed, showcasing the potential of ultra-low-dose contrast-enhanced PCD-CT for the detection of small vascular abnormalities while minimizing adverse effects on renal function.

[Ectopic Injection of Hydrogel Spacer in IMRT for Prostate Cancer-A Case Study].

A hydrogel spacer injection between the prostate and rectum is reported to reduce the risk of rectal toxicity in radiotherapy for prostate cancer. We present a case of an ectopic injection of hydrogel spacer. The patient was a 77-year-old male with intermediate-risk prostate cancer. It was planned that he would receive intensity modulated radiation therapy(IMRT), and a hydrogel spacer was inserted. Three days after insertion, the patient had a fever of 38.6℃ and presented frequent urination and perineal pain. Swelling and heat sensation were observed in the perineum. CRP was 12.00 mg/dL and the white blood cell count was as high as 9,300/µL. T2-weighted images showed a 5.3×1.9 cm high-intensity area around the lower urethra. Ectopic injection of hydrogel spacer and concomitant infection were diagnosed. Upon administering antibiotic treatment, his symptoms and inflammation improved immediately. Four months after hydrogel spacer insertion, T2-weighted images showed a high-intensity area in the lower urethra and around the ischial bone, which was attributed to the remaining hydrogel spacer. The hydrogel spacer and his symptoms completely disappeared at 9 months after hydrogel spacer insertion.

An Update on Embolization for Pulmonary Arteriovenous Malformations.

Pulmonary arteriovenous malformations are abnormal connections between a pulmonary artery and a pulmonary vein that can lead to ischemic stroke and brain abscess due to right-to-left shunting of blood. Embolization is currently considered the first treatment option for pulmonary arteriovenous malformations owing to its minimal invasiveness. This review updates the indications and techniques for the embolization of pulmonary arteriovenous malformations and determines the persistence of pulmonary arteriovenous malformations following embolization based on the most recent literature.

Carbon Dioxide Angiography for the Detection of Lower Gastrointestinal Arterial Bleeding Initially Occult to Angiography with Iodinated Contrast Media.

This study evaluated the utility of carbon dioxide (CO2) in angiography for the detection of lower gastrointestinal arterial bleeding initially occult to angiography with iodinated contrast media. Fourteen patients underwent CO2-enhanced angiography. In all patients, extravasation was identified by contrast-enhanced computed tomography but not by initial iodinated contrast-enhanced angiography. After iodinated contrast-enhanced angiography, CO2-enhanced angiography was performed from the same catheter position. The detection capability for extravasation on CO2-enhanced angiography was evaluated. CO2-enhanced angiography allowed for the visualization of extravasation and subsequent transcatheter arterial embolization in 11 of 14 (79%) cases, with extravasation seen during either CO2-enhanced angiography (n = 8) or subsequent repeat iodinated contrast-enhanced angiography immediately after negative CO2-enhanced angiography (n = 3). Conservative treatment was performed in the remaining 3 cases. In conclusion, CO2-enhanced angiography appears useful for identifying occult lower gastrointestinal bleeding.

Definitive radiotherapy with stereotactic or IMRT boost with or without radiosensitization strategy for operable breast cancer patients who refuse surgery.

For breast cancer (BC) patients who refused surgery, we developed a definitive treatment employing modern sophisticated radiation techniques. Thirty-eight operable BC patients were treated by conventionally fractionated whole-breast (WB) radiotherapy in combination with stereotactic (for primary tumor) or intensity-modulated (for primary tumor with/without regional lymph nodes [LN]) radiotherapy (IMRT) boost. Standard doses were 50 Gy/25 fractions, 21 Gy/3 fractions and 20 Gy/8 fractions, respectively, for the three radiation modalities. Disease stages were 0 (ductal carcinoma in situ [DCIS]) in seven patients, I in 12, II in 16 and III in three. In 26 patients, intratumoral hydrogen peroxide injection or hyperthermia with oral tegafur-gimeracil-oteracil potassium (S-1) was also used to sensitize the tumors to radiation. Hormonal and standard systemic therapy were administered in 25 and 13 patients, respectively. Complete and partial responses were obtained in 19 patients each; in patients with partial response, no further regrowth of the residual mass was observed, except for two patients who developed local recurrence. During a follow-up of 8-160 months (median, 50 months for living patients), two, one and two patients developed local relapse, sub-clavicular node metastasis and distant metastasis, respectively. The 5-year rates for overall, progression-free and local relapse-free survival were 97.2, 90.9 and 93.4%, respectively. Fourteen patients developed Grade 3 radiation dermatitis but all recovered after treatment. In 47%, the affected breast became better-rounded, and the nipple of the irradiated breast became higher by ≥1 cm than the contralateral nipple. Our method might be a treatment option for operable BC patients.

Utilization of an Occlusion Balloon Catheter during Stent-Graft Placement to Treat Postsurgical Visceral Arterial Hemorrhage.

The utility of occluding the bleeding artery using an occlusion balloon catheter during stent-graft placement for visceral artery bleeding was evaluated. Stent-graft placement for visceral artery bleeding was performed using a balloon catheter in 6 patients. All bleeding occurred after biliary or pancreatic surgery. Since 1 patient underwent the procedure twice, 7 procedures were assessed in total. Technical success, procedure-related adverse events, and 30-day mortality rates were evaluated. Technical success was defined as the placement of the stent-graft at the target site and the resolution of extravasation or pseudoaneurysm. In all procedures, stent-graft placement was successfully performed (technical success rate, 100%). Focal liver infarction occurred in 2 of 7 patients (29%), but did not require further treatment and was considered a minor adverse event. The 30-day mortality rate was 0%. In conclusion, the use of an occlusion balloon in the feeding artery facilitated successful stent-graft repair of hemorrhage from visceral arteries.

Embolization for acute arterial bleeding: use of the triaxial system and N-butyl-2-cyanoacrylate.

PURPOSE: The aim of this study was to evaluate the usefulness of transcatheter arterial embolization (TAE) using the triaxial system with N-butyl-2-cyanoacrylate (NBCA) for acute arterial bleeding in comparison to TAE using the triaxial system with gelatin sponges (GS)　and/or coils. MATERIAL AND METHODS: Between October 2013 and November 2018, 95 patients with acute arterial bleeding underwent emergency TAE using the triaxial system. Six patients underwent multiple TAEs and thus, 104 TAEs using the triaxial system were performed. In 26 of the 104 cases, TAE were performed with NBCA (NBCA group), and in the remaining 78 cases, TAE were performed with GS and/or coils (control group). RESULTS: Hemorrhagic shock and coagulopathy more often occurred in the NBCA group. Procedure time was shorter in the NBCA group. The technical success rate was 100% in both groups (p > 0.99). The clinical success rate in the NBCA and control groups was 92% and 96%, respectively (p = 0.6). There was one minor complication (4%, 1/26) of liver dysfunction in a patient of the NBCA group, but no complication in the control group (p = 0.26). CONCLUSION: TAE using the triaxial system with NBCA may be useful for acute arterial bleeding, especially in patients with hemorrhagic shock and coagulopathy.

Duodenal stenosis after transcatheter arterial embolization for rupture of an inferior pancreaticoduodenal aneurysm.

A 64-year-old man presented with epigastric pain and underwent contrast-enhanced computed tomography. Ruptured aneurysm of the inferior pancreaticoduodenal artery was diagnosed. TAE was successfully accomplished using coils, but vomiting appeared 9 days later. Duodenal stenosis was diagnosed from contrast-enhanced computed tomography and upper gastrointestinal endoscopy and was attributed to edematous changes in the duodenum. Conservative management led to successful recovery and discharge.

Use of microspheres in embolization for unruptured renal angiomyolipomas.

PURPOSE: To describe our initial experience with use of microspheres in transcatheter arterial embolization (TAE) for unruptured sporadic renal angiomyolipomas (AMLs). MATERIALS AND METHODS: Seven consecutive patients with seven unruptured sporadic renal AMLs, 6 females and 1 male, with a median age of 45 years (range, 30-69 years), underwent TAE using microspheres between November 2016 and February 2020. We evaluated the technical success rate, complications related to the procedure, clinical success rate, and the shrinkage rate of renal AML. Technical success was defined as the completion of TAE. Clinical success was defined as presence of shrinkage of the renal AML after TAE. RESULTS: In all patients, TAE using microspheres was accomplished and technical success rate was 100% (7/7). Three patients exhibited slight pain, but it improved with only observation, and the minor complication rate was 43% (3/7) and major complication rate was 0% (0/7). After the TAE, shrinkage of renal AML was confirmed in 6 of 7 patients, and clinical success rate was 86% (6/7). The median of shrinkage rate was 47% (range, 26-83%) with a median follow-up period of 19 months (range, 4-30 months). CONCLUSION: TAE using microspheres appears to be effective and safe for unruptured sporadic renal AMLs.

Safety and utility of performing CT-guided biopsies of pulmonary lesions that arise after radiotherapy.

This study aimed to evaluate the feasibility, safety and usefulness of performing computed tomography (CT)-guided biopsies of pulmonary lesions that arise after radiotherapy. Seventeen patients (14 males and 3 females; median age: 69 years, range: 48-84 years) underwent CT-guided biopsies of pulmonary lesions that occurred in lung regions that had previously been treated with radiotherapy. Three patients underwent CT-guided biopsies twice, and thus, the total number of procedures was 20. We reviewed the subjects' medical records and images, and evaluated the rate for obtaining pathological diagnosis with the biopsy sample, subsequent clinical course, and complications associated with the procedure. In 19 of 20 procedures (95%), the CT-guided biopsy resulted in a pathological diagnosis being obtained. In 14 procedures, the pathological results were consistent with the patients' clinical courses. In the remaining 5 procedures, the lesions were pathologically diagnosed as benign, but they increased in size thereafter; so the lesions were considered to be clinically malignant. The results were considered to represent sampling errors. There were 3 minor complications (slight pneumothorax which did not require drainage) (3/20, 15%), and there were no major complications. In conclusion, performing CT-guided biopsies of pulmonary lesions that arise after radiotherapy appears to be feasible, safe and useful.

Safety of Transcatheter Arterial Embolization for Visceral Artery Pseudoaneurysms: Incidence of Intraprocedural Rupture.

INTRODUCTION: Transcatheter arterial embolization is the first-line treatment for visceral artery pseudoaneurysms (VAPAs); however, the intraprocedural rupture of pseudoaneurysms is an important complication. The present study was performed to evaluate the safety of embolization for VAPAs, including the incidence of intraprocedural rupture. METHODS: Among 56 consecutive patients with 57 VAPAs who underwent treatment between April 2009 and October 2020, 46 patients with 47 VAPAs underwent embolization. Complications related to embolization including intraprocedural rupture, the technical success rate, and clinical outcomes were evaluated. Complications that required extended hospitalization, an advanced level of care, or resulted in permanent adverse sequelae or death were classified as major complications, while the remainder were considered to be minor. Technical success was defined as the completion of embolization. RESULTS: The intraprocedural rupture of pseudoaneurysms occurred in 3 out of 47 VAPAs treated with embolization (6%) and resulted in minor complications. One liver abscess requiring drainage was regarded as a major complication (2%). Focal infarction after embolization was observed as a minor complication in 20 cases. Complications occurred in 24 out of 47 cases (51%), comprising one major complication (2%) and 23 minor complications (48%). The technical success rate was 100% (47/47). Fifty-three out of 56 patients (95%) were alive in a median follow-up period of 18 months (range: 2 days-137 months). CONCLUSIONS: Embolization is safe and useful for the treatment of VAPAs; however, the intraprocedural rupture of pseudoaneurysms may occur, and, thus, care is needed during this procedure.

Multiple large pancreaticoduodenal artery aneurysms due to celiac artery occlusion: Combination of the aorto-hepatic bypass and coil embolization with a dual approach through both the superior mesenteric artery and bypass.

Pancreaticoduodenal artery aneurysm can occur from occlusion or stenosis of the celiac artery due to arteriosclerosis or median arcuate ligament compression. The risk of rupture of the aneurysm is independent of the aneurysmal diameter. A 78-year-old woman presented with multiple large aneurysms of the anterior superior pancreaticoduodenal artery. To preserve arterial flow to the liver, bypass grafting from the supra-celiac aorta to the common hepatic artery was performed at first. Coil embolization was successfully performed 10 days later with a dual approach through both the superior mesenteric artery and bypass. It was considered that the combination of the aorto-hepatic bypass and coil embolization was effective for the pancreaticoduodenal artery aneurysms due to celiac artery occlusion.

Feasibility of transrectal and transperineal fiducial marker placement for prostate cancer before proton therapy.

BACKGROUND: To compare the feasibility of transrectal and transperineal fiducial marker placement for prostate cancer before proton therapy. MATERIALS AND METHODS: From 2013 to 2015, the first 40 prostate cancer patients that were scheduled for proton therapy underwent transrectal fiducial marker placement, and the next 40 patients underwent transperineal fiducial marker placement (the first series). Technical and clinical success and pain scores were evaluated. In the second series (n = 280), the transrectal or transperineal approach was selected depending on the presence/absence of comorbidities, such as blood coagulation abnormalities. Seven patients refused to undergo the procedure. Thus, the total number of patients across both series was 353 (262 and 91 underwent the transrectal and transperineal approach, respectively). Technical and clinical success, complications, marker migration and the distance between the two markers were evaluated. RESULTS: In the first series, the technical and clinical success rates were 100% in both groups. The transrectal group exhibited lower pain scores than the transperineal group. The overall technical success rates of the transrectal and transperineal groups were 100% (262/262) and 99% (90/91), respectively (P > 0.05). The overall clinical success rate was 100% in both groups, and there were no major complications in either group. The migration rates of the two groups did not differ significantly. The mean distance between the two markers was 25.6 ± 7.1 mm (mean ± standard deviation) in the transrectal group and 31.9 ± 5.2 mm in the transperineal group (P < 0.05). CONCLUSION: Both the transrectal and transperineal fiducial marker placement methods are feasible and safe.

Use of 0.014-in. pushable bare platinum coils in super-selective embolization through the 1.6-Fr. microcatheter of the triaxial system.

BACKGROUND: A triple-coaxial (triaxial) system, which consists of a small microcatheter, a large microcatheter, and a 4-Fr. catheter, has been reported to allow super-selective catheterization. A 1.6-Fr. microcatheter has recently become available as the small microcatheter for the triaxial system, in addition to 0.014-in. pushable bare platinum coils that may be introduced into the 1.6-Fr. microcatheter. PURPOSE: The purpose of the present study was to evaluate the feasibility of 0.014-in. pushable bare platinum coils in embolization through the 1.6-Fr. microcatheter of the triaxial system. MATERIAL AND METHODS: Between November 2015 and October 2019, 19 embolizations were performed on 18 patients, 9 males and 9 females with a median age of 77 years (range, 41-88 years), using 0.014-in. pushable bare platinum coils through the 1.6-Fr. microcatheter of the triaxial system. The technical success rate, clinical success rate, and complications associated with the procedure were assessed. Technical success was defined as the successful delivery and placement of 0.014-in. pushable bare platinum coils, and clinical success as the immediate postembolic complete cessation of blood flow confirmed by digital subtraction angiography. RESULTS: Eighty-four 0.014-in. pushable bare platinum coils were delivered and 19 arteries were successfully embolized. The median number of 0.014-in. pushable bare platinum coils was 4 (range, 1-12). The technical success rate was 100% (84/84) and the clinical success rate was also 100% (19/19). There were no complications associated with the procedures. CONCLUSION: The use of 0.014-in. pushable bare platinum coils in super-selective embolization through the 1.6-Fr. microcatheter of the triaxial system appears to be feasible and safe.

Advanced monoenergetic reconstruction technique for dual-energy computed tomography to evaluate endoleaks after endovascular stent-graft placement.

PURPOSE: To evaluate the usefulness of the advanced monoenergetic imaging (AMI) reconstruction technique for dual-energy computed tomography to evaluate endoleaks after endovascular stent-graft placement. MATERIALS AND METHODS: Ninety-five dual-phase (early and delayed phases) enhanced CT examinations were performed for 60 patients who underwent endovascular stent-graft placement. AM images were reconstructed at 40 keV and compared with the standard 120-kVp images (SI). The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the aorta and endoleak were measured. Two radiologists subjectively assessed endoleak delineation and contrast enhancement conditions using a 5-point Likert scale (1: poor-5: excellent). RESULTS: Mean SNRs of the aorta were higher by AMI (early; 34.7 ± 10.2 [SD], delay; 11.4 ± 3.2) than by SI (early; 23.1 ± 6.3, delay; 8.6 ± 2.2) (P < 0.001). SNRs of the endoleak were higher by AMI (early; 26.3 ± 7.5, delay; 10.5 ± 3.1) than by SI (early; 18.2 ± 4.7, delay; 8.3 ± 2.1) (P < 0.001). CNRs by AMI (early; 32.9 ± 9.8, delay; 8.9 ± 2.8) were higher than those by SI (early; 19.5 ± 6.0, delay; 4.7 ± 1.6) in both phases (P < 0.001). Endoleak delineation and contrast enhancement conditions by AMI (4.4 ± 1.0 and 4.5 ± 0.6) were higher than those by SI (3.4 ± 1.0 and 3.3 ± 0.8) in the delayed phase (P < 0.001). There was no difference in the early phase. CONCLUSION: AMI may be useful for evaluating endoleaks after endovascular stent-graft placement.

Feasibility and Safety of Sac Embolization Using N-Butyl Cyanoacrylate in Emergency Endovascular Aneurysm Repair for Ruptured Abdominal Aortic Aneurysms or Isolated Iliac Artery Aneurysms.

PURPOSE: To evaluate the feasibility and safety of sac embolization with N-butyl cyanoacrylate (NBCA) in emergency endovascular aneurysm repair (EVAR) for ruptured abdominal aortic aneurysm (AAA) and iliac artery aneurysm (IAA) in comparison to EVAR without sac embolization. MATERIALS AND METHODS: Between February 2012 and December 2019, among 44 consecutive patients with ruptured AAA or IAA, 29 underwent EVAR. Of these, 22 patients (median age 77.5 years; 18 men) had concomitant sac embolization using NBCA; the remaining 7 patients (median age 88 years; 6 men) underwent EVAR without sac embolization and form the control group. The technical success, clinical success (hemodynamic stabilization), procedure-related complications, and mortality were compared between the groups. RESULTS: All EVAR procedures and embolizations were successful. The clinical success rates in the NBCA and control groups were 95% (21/22) and 71% (5/7), respectively (p=0.14). There was no complication related to the procedure. Type II endoleak occurred in 4 of 21 patients (19%) in the NBCA group vs none of the control patients. One patient (5%) died in the NBCA group vs 3 (43%) in the controls (p=0.034). CONCLUSION: Sac embolization using NBCA in emergency EVAR appears to be feasible and safe for ruptured AAA and IAA.

Treatment of pulmonary arteriovenous malformations: clinical experience using different embolization strategies.

PURPOSE: To evaluate embolization efficacy of pulmonary arteriovenous malformations (PAVM) using Amplatzer vascular plugs (AVP) and coils. MATERIALS AND METHODS: Eighty-eight embolized simple PAVMs in 38 patients were retrospectively analyzed by follow-up CT. Mean age was 50.2 ± 15.6 years and 22 (57.9%) patients were females. Mean follow-up interval was 38.2 ± 28.4 months (median 29.9 months). Embolization devices included AVP I, AVP II, AVP 4, and coils. Technical success was defined as no visualization of an early draining vein at angiography after embolization. Treatment success was defined as complete disappearance or decrease in size of the venous aneurysm ≥ 70% at follow-up CT. RESULTS: Technical success rate was 100% and treatment success rate evaluated by CT for the various embolization strategies was 100% for AVP I (n = 6), 100% for AVP I + coils (n = 5), 83.3% for AVP II (n = 6), 40.0% for AVP II + coils (n = 5), 87.5% for AVP 4 (n = 8), 50.0% for AVP 4 + coils (n = 8), and 78.0% for coils alone (n = 50). No statistically significant difference in embolization efficacy was seen between different devices (P = 0.083). Although not statistically significant, combination use of coils with AVPs demonstrated lower rates of clinical embolization success (P = 0.053). CONCLUSION: Embolization of PAVMs demonstrated high technical and treatment success rates with available embolic devices. No significant statistical differences were demonstrated between AVPs. However, the need for both coils and AVPs may suggest a more complicated underlying lesion at risk for recurrence.

Intraoperative Findings of an Atypical Type II Endoleak from an Artery within the Aneurysmal Wall after Endovascular Aneurysm Repair.

A 75-year-old man underwent emergent endovascular aortic repair for a ruptured abdominal aortic aneurysm. Two years later, computed tomography revealed aneurysm enlargement with endoleaks. Next, late open conversion was performed. Intraoperatively, we detected a spurting type II endoleak from an artery within the aneurysmal wall, which was unconnected to any branch vessels outside the aneurysm, and surgical ligation and sacotomy was performed uneventfully. To our knowledge, this is the first report to intraoperatively identify a type II endoleak from an artery within the aneurysm wall. Even for atypical type II endoleak, such as this case, open surgical repair should be effective.

Use of a steerable triaxial system for challenging catheterization.

Purpose: A steerable triaxial system consisting of a small microcatheter, a high-flow steerable microcatheter, and a 4-Fr. catheter is currently used in clinical settings. The purpose of the present study was to evaluate the efficacy and safety of the steerable triaxial system for challenging catheterization.Material and methods: Sixteen patients underwent an interventional procedure with the steerable triaxial system. Medical records and images of the procedures were reviewed, and the technical success rate, clinical success rate, and complications related to the procedures were evaluated. Technical success was defined as successful catheterization to the target artery using the steerable triaxial system, and clinical success as completion of the aimed procedure.Results: Catheterization to the target artery was successfully performed with the steerable triaxial system in 14 out of 16 patients, but was unsuccessful in two. Therefore, the technical success rate was 88% (14/16). The procedure was successfully accomplished in the 14 technical success patients. Thus, the clinical success rate was 88% (14/16). There were no complications related to the procedures.Conclusions: The steerable triaxial system has potential as a useful and safe technique for challenging catheterization.