Test Injection Method Research Articles

Preoperative tumor marking with indocyanine green (ICG) prior to minimally invasive colorectal cancer: a systematic review of current literature.

To describe the currently available evidence regarding the efficacy and safety of preoperative tumor marking using indocyanine green (ICG) prior to laparoscopic or robotic colorectal resections. A systematic search for relevant studies was conducted using the following databases: Embase (OVID), MEDLINE® (OVID), APA PsycInfo (OVID), Global Health (OVID) and HMIC Health Management Information Consortium (OVID) through June 2022 reported according to PRISMA 2020 guidelines. Primary outcome was the detection rate of the tumor sites preoperatively marked with ICG. Secondary outcomes were timing of ICG injection in days prior to the operation and technique-related complications. Eight single center studies, published between 2008 and 2022, were identified yielding a total of 1,061 patients, of whom 696 were preoperatively tattooed with ICG. Injection dosage of diluted ICG ranged from 0.1-1.5 ml. Four studies used the saline test injection method prior to ICG injection. When the marking was placed within one week, the visualization rate was 650/668 (97%), whereas when it was longer than one week, the detection rate was 8/56 (14%). No severe complications were reported. Preoperative tumor marking using ICG prior to minimally invasive colorectal resections is safe and effective, allowing intraoperative tumor site location when performed up to a week prior to surgery without disturbing the surgical view in potential mild complications.

Utility of the Contrast Injection Technique Using the Diluted Test Injection Method and the Test Bolus Tracking Method in the Coronary CT Angiography

Although the test bolus tracking method is available as a predicting method of scan timing in the coronary computed tomography (CT) angiography, it is known that there is a problem of scan timing due to the use of a part of test bolus method. The diluted test bolus method was adopted for test bolus, and as a result of using in combination with the test bolus tracking method, it showed a higher contrast enhancement compared with the test bolus tracking method; a stable contrast enhancement with less variation in CT number was obtained. The CT number at the peak in the test scan and the CT number of the main scan showed a high correlation. The contrast injection technique using the diluted test bolus method and the test bolus tracking method is a useful method in the coronary CT angiography. We named this contrast injection technique diluted test bolus tracking method.

Use of a novel shorter minimum caliber needle for creating endoscopic tattoos for preoperative localization: a comparative ex vivo study.

Background and study aims In colorectal cancer surgery, inadvertent deep injections during endoscopic tattooing can cause India ink leakage into the peritoneum, leading to complications or to poor visualization of the surgical plane. This ex vivo animal study compared the use of novel shorter, minimum caliber needles versus conventional injection needles for endoscopic tattooing. Animals and methods Four endoscopists used the novel needles and conventional needles to make ten endoscopic tattoos (five tattoos/needle type/endoscopist) in harvested porcine rectum using a saline test-injection method. India ink leakage and the success of the tattoo (i. e. visible, < 40 mm, plus no India ink leakage) were compared. Results India ink leakage was observed for 30 % (6/20) of the conventional needle tattoos but for none of the novel needle tattoos ( P = 0.02). Tattoos created using the novel needles were more successful than those made with the conventional needles: 18/20 (90 %) vs. 11/20 (55 %); P = 0.01. Conclusions The use of novel shorter minimum caliber needles may be safe and effective for endoscopic tattooing for preoperative localization prior to colorectal cancer surgery.

Optimization of scan timing for aortic computed tomographic angiography using the test bolus injection technique.

With fast computed tomography (CT), it is possible for the scanning to outpace the contrast medium bolus during aortic CT angiography (CTA). To evaluate the effectiveness of a new method for reducing the risk of outpacing in which the scan start timing (ST) and speed can be estimated from the peak enhancement time measured at the femoral artery using a single test-bolus injection (femoral artery test injection method [FTI method]). In 30 cases of aortic CTA, we measured the time to peak enhancement at the femoral artery (TPF) and the ascending aorta (TPA) with test-bolus injection performed twice in each examination. From the resultant linear relationship between TPF and transit time (TT = TPF - TPA), we developed a method for determining the ST and TT from TPF. One hundred patients were assigned to two groups: FTI and bolus tracking (BT), each with 50 patients. CT values were measured in main vessels (ascending aorta, descending aorta, femoral artery). The CT values of the vessels and the rate of cases with more than 300 HU (good cases) were compared between the two groups. The enhancement in the FTI method was significantly higher than that of the BT method (average CT values: FTI, 388.3 ± 52.4; BT, 281.2 ± 59.1; P < 0.001). The rates of good cases for FTI and BT were 86.0% and 46.0%, respectively. The FTI method was very effective in reducing the risk of outpacing of the contrast medium transit in aortic CTA without the need for an additional contrast medium dose.

Optimized Subtraction Coronary CT Angiography Protocol for Clinical Use with Short Breath-Holding Time—Initial Experience

Subtraction coronary computed tomography (CT) angiography (CCTA), which enables the removal of calcium and coronary stents from CCTA images, has been clinically introduced on a second-generation 320-row CT scanner. However, this technique for clinical use is not optimized. The long breath-holding time for two data acquisitions, which causes image misregistration and patient's discomfort, may limit the clinical availability of this subtraction technique. This study received approval from the institutional review board; prior informed consent to participate was obtained from all patients. We performed subtraction CCTA of five patients using the test injection method and optimized the interval time between the first (pulmonary-arterial phase) and the second (coronary-arterial phase) scans to achieve robust subtraction. The patients' breath-holding times were recorded. We compared breath-holding times between our new protocol and previous study's protocol (estimated). Mean breath-holding time in our new protocol was 18.3±3.4 seconds and that in previous protocol was 29.8±3.6 seconds (difference in mean breath-holding time was 11.5 seconds). Misregistration artifacts were not shown in final subtraction CCTA images. These images improved luminal visualization in the calcified lesion. Our test injection protocol can shorten the breath-holding time, which is helpful for successful subtraction CCTA imaging, potentially resulting in an increase of subtraction CCTA examinations in many institutions.

Timing of the hepatic arterial phase at Gd‐EOB‐DTPA‐enhanced hepatic dynamic MRI: Comparison of the test‐injection and the fixed‐time delay method

To compare the fixed-time- and the test-injection method with respect to the image quality of hypervascular hepatocellular carcinoma (HCC) and the adequacy of timing of the hepatic arterial phase (HAP) in Gd-EOB-DTPA (EOB) enhanced MRI. We studied 63 patients with computed tomography (CT) -proven hypervascular HCC: 30 (group 1) were scanned HAP using the fixed-time delay method (protocol 1); in the other 33 (group 2), we applied the test-injection method (protocol 2). We compared the protocols with respect with tumor-to-liver contrast (TLC), contrast-to-noise-ratio (CNR), and relative enhancement of the liver and tumor (REL , RET ) during HAP. Two radiologists compared the adequacy of HAP, image contrast, image noise, and overall image quality. Under protocol 2, TLC, CNR, and REL and RET of hypervascular HCC were significantly higher (P < 0.01). The proportion of optimal HAP was significantly higher for protocol 2 than protocol 1 (P < 0.01). The visual score of the image contrast and the overall image quality were significantly higher in group 2 than group 1 (P = 0.02 and P = 0.01, respectively). At EOB-enhanced hepatic dynamic MRI, the test-injection method yielded better image quality of hypervascular HCC and improved adequacy of timing of HAP.

Cerebral CT angiography using a small volume of concentrated contrast material with a test injection method: optimal scan delay for quantitative and qualitative performance

The objective of this study was to determine the optimal scan delay quantitatively and qualitatively in cerebral CT angiography (CTA) with a test injection method at the circle of Willis (cW). 66 consecutive patients suspected of having unruptured intracranial aneurysms underwent CTA using 40 ml of 370 mg iodine ml(-1) contrast material (CM). After the time until CM arrival at the cW (T(cW)) was calculated, scan delay was divided into three groups according to T(cW) and scan duration (SD) between the second cervical vertebra and cW as follows: [(T(cW)+6)-SD] in 21 patients (Group A); [(T(cW)+8)-SD] in 23 patients (Group B); and [(T(cW)+10)-SD] in 22 patients (Group C). Arterial and venous attenuation in the intracranial vessels was measured. Mean attenuation values were compared quantitatively. The arterial enhancement and venous overlap at the cW and above the cW were qualitatively compared among the three groups. Mean arterial attenuation in Groups B and C was significantly higher than that in Group A. Mean venous attenuation in Group C was significantly higher than those in Groups A and B. Arterial enhancement above the cW showed a significant difference between Groups A and C, and at the cW between Groups A and B, and Groups A and C. There was a significant difference in venous overlap among the three groups, except for that at the cW between Groups B and C. Setting scan delay as [(T(cW)+8)-SD] s can produce the best performance both quantitatively and qualitatively.

Abstract 8796: Comparison of Coronary Flow Velocity Reserve Measurement by Transthoracic Doppler Echocardiography with 320-Row Multidetector Computed Tomography Coronary Angiography for Predicting Coronary Artery Stenosis in Calcified Lesions in the Three Major Coronary Arteries

Objectives: This study examined the diagnostic accuracy of coronary flow velocity reserve (CFR) measurement using transthoracic Doppler echocardiography (TTDE) by comparing 320-row multidetector computed tomography coronary angiography (CTCA) for predicting coronary artery stenosis in calcified lesions in the 3 major coronary arteries. Methods and Results: Invasive coronary angiography (ICA), CTCA, and CFR measurement were performed in 101 patients. The presence of stenosis ≥50% was considered significant stenosis by ICA. By CTCA, the degree of coronary artery calcification was assessed using the Agatston calcium score (CS) method. Prospectively electrocardiographically-gated CTCA was performed with the use of test-injection method for the assessment of coronary artery stenosis. Coronary flow velocity was recorded in each target coronary artery by TTDE at rest and during hyperemia induced by intravenous infusion of adenosine triphosphate. CFR &lt;2, calculated as the ratio of hyperemic to basal peak and mean diastolic velocity, was considered ≥50% stenosis. Results: A significant coronary stenosis by ICA was found in 60 vessels. Coronary artery legions were successfully assessed in 91% and 95% of all vessels by CTCA and TTDE, respectively. CTCA had a sensitivity of 92%, a specificity of 93%, a positive predictive value (PPV) of 73%, and a negative predictive value (NPV) of 98% in patients with 0-299 CS, and had a sensitivity of 89%, a specificity of 67%, a PPV of 47%, and an NPV of 95% in patients with 300-599 CS for predicting coronary artery stenosis. In patients with ≥ 600 CS, 73% of vessels were unassessable. CFR&lt;2.0 had a sensitivity of 90%, a specificity of 90%, a PPV of 71%, and an NPV of 97% in patients with 0-299 CS, had a sensitivity of 92%, a specificity of 89%, a PPV of 79%, and an NPV of 96% in patients with 300-599 CS, and had a sensitivity of 100%, a specificity of 85%, a PPV of 77%, and an NPV of 100 % in patients with ≥ 600 CS for predicting coronary artery stenosis. Conclusions: CFR measurement accurately predicts significant coronary artery stenosis irrespectively of the degree of coronary artery calcification whereas progression of coronary calcification negatively influences diagnostic accuracy of CTCA-based assessment of coronary artery stenosis.

Small-Dose India Ink Tattooing for Preoperative Localization of Colorectal Tumor

India ink tattooing is widely used for tumor localization; however, the tattooing procedure is not yet standardized. This study aims to evaluate the efficacy of small-dose tattooing with sterile India ink using a saline test-injection method. Between April 2009 and August 2009, 20 patients underwent colonoscopic tattooing with prepackaged sterile India ink before resection of colorectal tumor. We injected 0.5 cc of India ink at three circumferential sites at the distal tumor using a saline test-injection method. Observation and leakage of India ink were evaluated during laparoscopic surgery, and the diameter of tattooing in the specimen was assessed. Tattoos were observed intraoperatively in 18 patients (90%). In 2 patients, tattoos were not observed on the serosal surface but were detected on the mucosal surface. Localized leakage of ink was identified during surgery in 1 patient (5%), without fever or abdominal pain. Mean tattoo diameter was 2.1 cm on the serosal surface and 2.0 cm on the mucosal surface. Small-dose tattooing with sterile India ink using a saline test-injection method is effective for tumor localization.

Dilution method of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd‐EOB‐DTPA)‐enhanced magnetic resonance imaging (MRI)

To elucidate whether a contrast agent dilution method (dilution method), in which gadoxetate disodium (Gd-EOB-DTPA) is diluted with saline, is useful for good-quality arterial-phase images. In this study we observed 494 hypervascular hepatocellular carcinomas (HCCs) in 327 patients with chronic liver disease. Three Gd-EOB-DTPA injection methods were adopted for comparison: 1) test injection method (undiluted Gd-EOB-DTPA and modified scan delay), in which a test dose of 0.5 mL of Gd-EOB-DTPA was injected to determine scan delay; 2) conventional method (undiluted Gd-EOB-DTPA and fixed scan delay); and (3) dilution method (diluted Gd-EOB-DTPA and fixed scan delay), in which Gd-EOB-DTPA was diluted to 20 mL with saline. Lesion-liver contrast was calculated. Image quality and lesion detectability were evaluated by two radiologists blinded to the injection methods. The lesion-liver contrast of the dilution method was significantly higher than that of the other two methods. Lesion detectability of the conventional method (64%) was significantly lower than that of the other two methods (contrast agent dilution method, 95%; test injection method, 93%). The image quality of the contrast agent dilution method was significantly better than that of the other two methods. The dilution method contributed to improved image quality, high lesion-liver contrast, and high lesion detectability in the arterial-phase images of GD-EOB-DTPA-enhanced MRI.

新しい造影方法であるｔｅｓｔ ｂｏｌｕｓ ｔｒａｃｋｉｎｇ法の開発と，冠状動脈ＣＴ造影検査における有用性について

The test bolus tracking (TBT) method is a new injection method of contrast medium that we developed. The TBT method is an injection technique that continuously performs the test bolus injection and the main bolus injection, such that the best acquisition of scan timing and the improvement of examination efficiency can be expected. We compared the TBT method and the test injection method by coronary CT angiography. The results demonstrated that the contrast enhancement of the coronary arteries was high and the variation of the CT value was also small in the TBT method. When the scan timing expected by the TI method and the TBT method were compared, it was different of two seconds or more by the case with 43%. However, the variation of CT value was small for the TBT method in these cases. Therefore, the TBT method is a very useful method for CCTA.

The usefulness of preoperative colonoscopic tattooing using a saline test injection method with prepackaged sterile India ink for localization in laparoscopic colorectal surgery

Laparoscopic surgery for colorectal neoplasm requires precise tumor localization. The authors have assessed the safety and efficacy of colonoscopic tattooing using a saline test injection method with prepackaged sterile India ink for tumor localization in laparoscopic colorectal surgery. Between July 2004 and January 2007, 63 patients underwent colonoscopic tattooing using prepackaged sterile India ink before laparoscopic surgery of colorectal tumors. Patient medical records and operation videos were retrospectively assessed. Tattoos were visualized intraoperatively in 62 (98.4%) of the 63 patients, and colorectal tumors were accurately localized in 61 patients (96.8%). In one patient, the tattoo could not be detected, whereas in another patient, it was visualized but the serosal surface of the rectosigmoid colon was stained diffusely. Both of these patients underwent intraoperative colonoscopy. Localized leakages of ink were identified in six patients (9.5%) during surgery. However, five of these patients had no symptoms, and the sixth patient, who underwent polypectomy and tattooing simultaneously, felt mild chilling without fever or abdominal pain. Preoperative colonoscopic tattooing using a saline test injection method with prepackaged sterile India ink is a safe and effective method for tumor localization in laparoscopic colorectal surgery.