OBJECTIVE: Coronary CT angiography (CCTA) has recently been established as a first-line test in patients with suspected coronary artery disease (CAD). Due to the increased use of CCTA, strategies to reduce radiation and contrast medium (CM) exposure are of high importance. The aim of this study was to evaluate the performance of automated tube voltage selection (ATVS)-adapted CM injection protocol for CCTA compared to a clinically established triphasic injection protocol in terms of image quality, radiation exposure, and CM administration MATERIAL AND METHODS: Patients undergoing clinically indicated CCTA were prospectively enrolled from July 2021 to July 2023. Patients underwent CCTA using a modified triphasic CM injection protocol tailored to the tube voltage by the ATVS algorithm, in a range of 70 to 130 kV with a 10 kV interval. The injection protocol consisted of two phases of mixed CM and saline boluses with different proportions to assure a voltage-specific iodine delivery rate, followed by a third phase of saline flush. This cohort was compared to a control group identified retrospectively and scanned on the same CT system but with a standard triphasic CM protocol. Radiation and contrast dose, subjective and objective image quality (contrast-to-noise-ratio [CNR] and signal-to-noise-ratio [SNR]) were compared between the two groups.
RESULTS: The final population consisted of 120 prospective patients matched with 120 retrospective controls, with 20 patients in each kV group. The 120 kV group was excluded from the statistical analysis due to insufficient sample size. A significant CM reduction was achieved in the prospective group overall (46.0 [IQR 37.0-52.0] vs. 51.3 [IQR 40.1-73.0] mL, p < 0.001) and at all kV levels too (all pairwise p < 0.001). There were no significant differences in radiation dose (6.13 ± 4.88 vs. 5.97 ± 5.51 mSv, p = 0.81), subjective image quality (median score of 4 [3-5] vs. 4 [3-5], p = 0.40), CNR, and SNR in the aorta and the left anterior descending coronary artery (all p > 0.05).
CONCLUSIONS: ATVS-adapted CM injection protocol allows for diagnostic quality CCTA with reduced CM volume while maintaining similar radiation exposure, subjective and objective image quality.

BACKGROUND: Octreotide is widely used for the treatment of acromegaly, neuroendocrine tumors, and secretory diarrhea. However, long-term octreotide treatment can increase the incidence of gallstones. Vicarious contrast medium excretion (VCME) through the hepatobiliary system is well known. However, few studies have reported octreotide-induced acute gallstones following VCME.
METHODS: A 69-year-old man presented with left lower back pain and hematuria caused by a fall. The patient had a history of polycystic kidney disease. VCME occurred following renal artery embolization for a ruptured polycystic kidney. After 5 d of treatment with octreotide, the patient developed acute gallstones and intrahepatic cholestasis which further induced pancreatitis and cholangitis. He was discharged after hemodialysis, antibiotics, and supportive treatments.
CONCLUSIONS: For patients with a high-risk of VCME, octreotide should be cautiously administered and carefully monitored.

BACKGROUND: Spinal nerve block is difficult with minimally invasive cardiac surgery (MICS), because of the risk of serious bleeding complications due to full heparinization. Continuous extrapleural intercostal nerve block (CEINB) is a postoperative pain treatment for intercostal thoracotomy, with fewer complications. Here, we report a case in which imaging evaluation of CEINB with contrast medium was conducted to anatomically confirm the spread of local anesthetics after MICS.
METHODS: A 65-year-old woman with severe mitral regurgitation underwent mitral valve plasty under general anesthesia via right-sided mini-thoracotomy. A CEINB catheter was placed before the incision was closed, without creating a conventional extrapleural pocket. We conducted an imaging evaluation with a contrast medium via the inserted catheter and confirmed sufficient spread around the intercostal nerve area. In addition, postoperative pain was well controlled by the nerve block.
CONCLUSIONS: Imaging evaluation of CEINB with contrast medium could increase analgesic quality and decrease complications post-MICS.

A 70-year-old woman with symptomatic bradycardia caused by persistent atrial fibrillation and atrioventricular block was referred to our institution for pacemaker implantation. After we failed to obtain adequate His bundle capture thresholds (>2.5 V at 1.0 ms) at three pacing sites, left bundle branch pacing was attempted as an alternative technique. The tip of the 3830 lead was screwed towards the left side of the interventricular septum. Contrast medium was injected through the C315 sheath, which was placed close to the right side of the interventricular septum to determine the exact depth of the 3830 lead inside the septum. Unexpectedly, the vessels in the interventricular septum were revealed by the contrast, which showed that the lead had penetrated one of the septal vessels. To the best of our knowledge, this is the first reported case of a patient in whom injection of a contrast agent through a delivery sheath showed damage to the interventricular septal vessels. Findings from this case suggest that injection of contrast medium through a C315 sheath that is placed close to the interventricular septum is a potential method for excluding damage to interventricular septal vessels.

Although ultrasonographically-guided carotid interventions without contrast medium have been reported in the literature, we found no report regarding stenting of the vertebral artery origin for treatment of stenosis. Here, we report the case of an iodine-allergic patient in whom a stenosis at the origin of the vertebral artery was successfully treated with ultrasonographically-guided stent placement without contrast medium. B-mode longitudinal images were monitored during the insertion of the embolism-protection device, when positioning the stent, and for the evaluation of the stent opening. This technique can be an alternative option in selected patients, especially those allergic to the contrast medium.

A 43-year-old male patient on maintenance hemodialysis had an enhanced computed tomography scan examination with iohexol for the first time 10 min before regular hemodialysis therapy. At the start of hemodialysis, no symptoms were observed, and the platelet count was 148,000/μl. Approximately 1 h after starting hemodialysis, dyspnea and chest discomfort appeared. Since oxygen saturation of the peripheral artery decreased to 87%, oxygen administration was immediately started while continuing hemodialysis therapy. Furthermore, gingival hemorrhage was observed, and the platelet count decreased to 5000/μl. We were carefully monitoring his conditions while continuing hemodialysis and oxygen administration, but no further deterioration was observed. Thereafter, these symptoms and severe thrombocytopenia gradually improved without additional treatment. At the end of hemodialysis, these symptoms completely disappeared. As well, the platelet count recovered to 35,000/μl at the end of hemodialysis and increased to 92,000/μl the next morning. From the clinical course, we diagnosed with contrast medium-induced thrombocytopenia. Acute thrombocytopenia is a rare complication induced by the contrast medium. Until now, 16 cases on contrast medium-induced thrombocytopenia have been reported. Our case spontaneously recovered from severe thrombocytopenia relatively earlier than previous reports. Our patient started hemodialysis therapy 10 min after an enhanced computed tomography examination. Early removal of contrast medium by hemodialysis might be associated with early improvement. We should acknowledge that contrast media have potential to induce severe thrombocytopenia, even in patients on maintenance hemodialysis.

Compartment syndrome is a rare but serious complication of contrast medium extravasation. To avoid permanent damage, it is important to recognize the symptoms quickly and immediately initiate treatment. We report a patient, who developed compartment syndrome of the forearm after extravasation of contrast medium and review the available literature on this subject. To our knowledge this is the first reported case of compartment syndrome of the forearm due to contrast medium application for a trauma CT in a patient that had no direct trauma to the affected limb.

We report a case of asymptomatic iatrogenic air bubbles in the left ventricle observed by coronary computed tomographic angiography. Air bubbles are rarely found in the left ventricle and could prove fatal should they migrate to the brain or coronary arteries. We believe that the cause is micro air bubbles in the tubing system between the intravenous catheter and power injector.

BACKGROUND: Contrast-induced acute kidney injury is one of the common adverse events related to percutaneous coronary intervention and a predictor for worse outcome. In the setting of percutaneous coronary intervention for chronic total occlusion, large amounts of contrast medium, more than 200-400 mL, are generally injected. A higher dose of contrast medium causes contrast-induced acute kidney injury more frequently. Therefore, patients who undergo chronic total occlusion-percutaneous coronary intervention are at risk for contrast-induced acute kidney injury.
METHODS: We present the case of a 77-year-old Japanese man with post-acute myocardial infarction angina pectoris, heart failure, and chronic kidney disease who underwent percutaneous coronary intervention for chronic total occlusion in his right coronary artery. In the procedure, the retrograde wire was a visible penetration mark that made contrast medium unnecessary. Contemporary reverse controlled antegrade and retrograde subintimal tracking was successfully achieved and stents were implanted without contrast medium. Contrast medium was injected two times after stent implantation to confirm coronary flow and no perforation. The total amount of contrast medium was only 8 mL for chronic total occlusion-percutaneous coronary intervention.
CONCLUSIONS: Chronic total occlusion-percutaneous coronary intervention with contemporary reverse controlled antegrade and retrograde subintimal tracking without contrast medium may be safe and feasible in selected patients.

A 51-year-old man recently diagnosed with preclinical Cushing\'s syndrome complained of chest oppression concomitant with back pain. Following contrast-enhanced computed tomography (CT) to rule out acute aortic dissection, he developed chest symptoms accompanied by elevation of blood pressure to 240/120 mmHg and ischemic electrocardiographic change. Urgent coronary angiography revealed a coronary artery aneurysm (15 mm × 6 mm) in the distal portion of the left anterior descending artery concomitant with coronary flow delay. Re-analysis of the blood sample taken at admission showed elevated plasma catecholamine concentrations, leading to a diagnosis of paroxysmal pheochromocytoma. An adrenal tumor was excised laparoscopically and histologically shown to be a pheochromocytoma. These findings show that coronary artery aneurysm may be a rare complication of pheochromocytoma, and indicate that monitoring of blood pressure or analysis of stored blood samples, if necessary, is essential to detect pheochromocytoma when using contrast medium or glucagon in patients known to have an adrenal incidentaloma. It should be noted that pre-treatment with an α-blocker is necessary when patients who are likely to have pheochromocytoma need to undergo contrast-enhanced CT. .