[Giant Thrombus in the Left Atrium Showing a Rapid Growth:Report of a Case].

A 74-year-old woman had been on hemodialysis for about 2 months using a short-term indwelling dialysis catheter due to chronic kidney disease. A 20 mm-diameter left atrial neoplastic lesion was noted during a screening echocardiogram performed at the time of induction of hemodialysis. The lesion rapidly increased to 30 mm 2 months later and was referred to our hospital for surgical resection. Under cardiopulmonary bypass and cardiac arrest, tumor resection was performed. Although the lesion was myxomatous with a thin stalk on the left atrial ceiling, the pathological diagnosis was thrombus. After the initiation of anticoagulation, the patient was discharged.

Mediastinal hematoma as an unusual intrathoracic manifestation of Boerhaave Syndrome: A case report.

INTRODUCTION: Boerhaave Syndrome (BS) is rare but life-threatening condition caused by a sudden increase in the intraluminal pressure due to vomiting. We present a case of BS manifesting as a posterior mediastinal hematoma, indicative of a potentially fatal condition. PRESENTATION OF CASE: A 51-year-old man presented with acute chest pain after vomiting. Enhanced Computed Tomography revealed mediastinal fluid with a left pleural effusion, leading to a diagnosis of BS. Emergency surgery revealed a posterior mediastinal hematoma with active bleeding due to a torn proper esophageal artery. Hemostasis and a wall repair were performed, and the patient was discharged uneventfully. DISCUSSION: This case highlights two important aspects. Firstly, a spontaneous esophageal perforation can manifest as a mediastinal hematoma due to the subpleural arterial injury, delaying bacterial spillage. While preoperative thoracentesis may not always diagnose BS accurately, bloody thoracic drainage can serve as an alternative diagnostic sign. Secondly, the mediastinal hematoma itself poses a serious risk, as it can lead to a catastrophic outcome even before bacterial contamination occurs, emphasizing the necessity of a timely surgical intervention in BS cases. CONCLUSION: BS can manifest as a mediastinal hematoma, and the absence of gastrointestinal content in the thoracic drainage does not rule out the possibility of BS. Prompt surgical intervention remains essential, as a mediastinal hematoma alone can result in a catastrophic outcome. This case highlights the significance of a comprehensive diagnostic assessment for BS.

The outcome of closure of inguinal hernia with laparoscopic percutaneous extraperitoneal closure in young adults.

BACKGROUND: Hernioplasty is one of the most commonly performed surgeries. However, the optimal procedure for young adults has not been defined yet. Our study compared the outcomes of laparoscopic percutaneous extraperitoneal closure (LPEC) in young adults with outcomes in children. MATERIAL AND METHODS: We retrospectively reviewed patients aged 0-30 years who underwent LPEC. Data regarding age, sex, hernia type, surgical time, pre-intraoperative laterality, contralateral patent processus vaginalis (CPPV), and complications were analyzed. RESULTS: LPEC was performed on 2642 patients in our hospital. Of these, 51 patients were young adults (aged 15-30 years). Asymptomatic CPPV in unilateral patients was frequent in the <15-year age group (50.2%) compared to the 15-30-year age group (15.9%). The median surgical time was shorter in the <15-year age group (19 min, interquartile range [IQR]: 24-33) compared to that of the 15-30-year age group (33 min, IQR: 23.3-40.8). CONCLUSIONS: This is the first report on the outcomes in young adult patients who underwent LPEC. The median surgical time was longer in the 15-30-year age group than in the <15-year age group. The median follow-up was 4.7 years with no intra-postoperative complications, such as postoperative bleeding, infection, persistent pain, and recurrence. LPEC is an effective, cosmetic, and safe surgical treatment in young adults and children.

[Requiring Differential Diagnosis of Pulmonary Arteriovenous Fistula and Pulmonary Venous Aneurysm: Report of a Case].

A pulmonary arteriovenous fistula (PAVF) is a direct abnormal connection between the pulmonary artery and pulmonary vein, lacking capillary tissue. On the other hand, a pulmonary venous aneurysm (PVA) is a localized dilation and aneurysmal formation in the pulmonary vein without reflux issues. Treatment approaches for PAVF and PVA differ, considering surgery or catheter embolization for PAVF due to the risk of cerebral infarction or rupture caused by the abnormal shunt. PVA cases, being rare in rupture and embolism, are usually recommended for observation. Therefore, distinguishing between these two conditions is crucial. This article presents a case where both PVA and PAVF were present, necessitating a differential diagnosis.

Evaluation of the widths of the mucosal strips in pathological examination of specimens of endoscopic submucosal dissection for early gastric cancer.

BACKGROUND: Endoscopic submucosal dissection (ESD) is the standard treatment for early gastric cancer in Japan. Pathological evaluation of ESD specimens is considered essential to determine if additional gastrectomy is necessary. Usually, specimens resected by ESD are sliced into 2-3 mm wide sections, and each section is examined for depth of tumor and lymphovascular invasion. Nevertheless, in most cases of additional gastrectomy, lymph node metastasis is not present. Given that there are few-studies on how clinical-decisions based on the pathologic-evaluation-method, in particular the specimen cut-width, influence patient outcomes, we retrospectively evaluated whether reducing the number of cuts to one-half or one-third would result in underestimation of the real need for additional surgery. The effect of the actual cut-width on recommended treatment (referral to operation) and patient-outcomes was also assessed. METHODS: Pathological records of 498 lesions from 439 patients were reviewed and re-evaluated. All pathological descriptions are based on the gastric cancer classification system of the Japanese Gastric Cancer Association, 15th edition. RESULTS: In 5.8% and 8.5% of the total specimens, underdiagnosis of tumor-depth and lymphovascular invasion occurred when the number of sections was reduced to one-half and one-third, respectively. Significantly more submucosal invasions were found in the group in which the cut-with was between 3 and 4 mm than in the group in which the cut width was less than 3 mm. CONCLUSION: Evaluation of the appropriate cut-width is important and should be discussed from the standpoint of labor costs and lost opportunities to search for molecular markers in ESD materials.

Out-of-Plane Needle Placements Using 3D Augmented Reality Protractor on Smartphone: An Experimental Phantom Study.

PURPOSE: To evaluate the accuracy of needle placement using a three-dimensional (3D) augmented reality (AR) protractor on smartphones (AR Puncture). MATERIALS AND METHODS: An AR protractor that can be rotated in three directions against the CT plane with angle guidance lines for smartphones was developed. The protractor center can be adjusted to an entry point by manually moving the smartphone with the protractor center fixed at the center of the screen (Fix-On-Screen) or by image tracking with a printed QR code placed at an entry point (QR-Tracking). Needle placement was performed by viewing a target line in the tangent direction with the Bull's eye method. The needle placement errors placed by four operators in six out-of-plane directions in a phantom using a smartphone (iPhone XR, Apple, Cupertino, CA, USA) were compared with two registration methods. RESULTS: No significant difference in the average needle placement error was observed between the Fix-On-Screen and QR-Tracking methods (5.6 ± 1.7 mm vs. 6.1 ± 2.9 mm, p = 0.475). The average procedural time of the Fix-On-Screen method was shorter than that of the QR-Tracking method (71.0 ± 23.9 s vs. 98.4 ± 59.5 s, p = 0.042). CONCLUSION: The accuracies of out-of-plane needle placements using the 3D AR protractor with the two registration methods were equally high, with short procedure times. In clinical use, the Fix-On-Screen registration method would be more convenient because no additional markers are required.

Noncontact measurement of puncture needle angle using augmented reality technology in computed tomography-guided biopsy: stereotactic coordinate design and accuracy evaluation.

PURPOSE: This study aims to introduce a new handheld device application for noncontact and real-time measurements of the angle of a biopsy needle using augmented reality (AR) image tracking technology. Furthermore, this study discusses the methods used to optimize the related coordinate design for computed tomography (CT)-guided biopsy procedures. METHODS: An in-house noncontact angle measurement application was developed using AR platform software. This application tracks the position and direction of a printed texture located on the handle of a biopsy needle. The needle direction was factorized into two directions: tilting or rolling. Tilting was defined following the tilting of the CT gantry so that rolling would match the angle measured in CT images. In this study, CT-guided tumor biopsies were performed using a conventional guiding method with a protractor. The true value of needle rolling was measured by CT imaging and was then compared to the rolling measurement provided by the application developed in the current study using a mobile phone. RESULTS: This study enrolled 18 cases of tumor biopsy (five renal tumors, five lung tumors, four retroperitoneal tumors, one soft tissue tumor, one thyroid tumor, one mesentery tumor, and one bone tumor). The measurement accuracy was - 0.2°, which was the average difference between AR and CT, and the measurement precision was 2.0°, which was the standard deviation of the difference between AR and CT measurements. The coefficient of determination (R2) was 0.996. CONCLUSION: The noncontact needle measurement software using AR technology is sufficiently reliable for use in clinical settings. A real-time display of the needle angle that also shows the direction of the CT gantry is expected to enable a simple biopsy needle navigation.

New standards for phantom image quality and SUV harmonization range for multicenter oncology PET studies.

Not only visual interpretation for lesion detection, staging, and characterization, but also quantitative treatment response assessment are key roles for 18F-FDG PET in oncology. In multicenter oncology PET studies, image quality standardization and SUV harmonization are essential to obtain reliable study outcomes. Standards for image quality and SUV harmonization range should be regularly updated according to progress in scanner performance. Accordingly, the first aim of this study was to propose new image quality reference levels to ensure small lesion detectability. The second aim was to propose a new SUV harmonization range and an image noise criterion to minimize the inter-scanner and intra-scanner SUV variabilities. We collected a total of 37 patterns of images from 23 recent PET/CT scanner models using the NEMA NU2 image quality phantom. PET images with various acquisition durations of 30-300 s and 1800 s were analyzed visually and quantitatively to derive visual detectability scores of the 10-mm-diameter hot sphere, noise-equivalent count (NECphantom), 10-mm sphere contrast (QH,10 mm), background variability (N10 mm), contrast-to-noise ratio (QH,10 mm/N10 mm), image noise level (CVBG), and SUVmax and SUVpeak for hot spheres (10-37 mm diameters). We calculated a reference level for each image quality metric, so that the 10-mm sphere can be visually detected. The SUV harmonization range and the image noise criterion were proposed with consideration of overshoot due to point-spread function (PSF) reconstruction. We proposed image quality reference levels as follows: QH,10 mm/N10 mm ≥ 2.5 and CVBG ≤ 14.1%. The 10th-90th percentiles in the SUV distributions were defined as the new SUV harmonization range. CVBG ≤ 10% was proposed as the image noise criterion, because the intra-scanner SUV variability significantly depended on CVBG. We proposed new image quality reference levels to ensure small lesion detectability. A new SUV harmonization range (in which PSF reconstruction is applicable) and the image noise criterion were also proposed for minimizing the SUV variabilities. Our proposed new standards will facilitate image quality standardization and SUV harmonization of multicenter oncology PET studies. The reliability of multicenter oncology PET studies will be improved by satisfying the new standards.

Mixed Reality Needle Guidance Application on Smartglasses Without Pre-procedural CT Image Import with Manually Matching Coordinate Systems.

PURPOSE: To develop and assess the accuracy of a mixed reality (MR) needle guidance application on smartglasses. MATERIALS AND METHODS: An MR needle guidance application on HoloLens2, without pre-procedural CT image reconstruction or import by manually matching the spatial and MR coordinate systems, was developed. First, the accuracy of the target locations in the image overlay at 63 points arranged on a 45 × 35 × 21 cm box and needle angles from 0° to 80°, placed using the MR application, was verified. The needle placement errors from 12 different entry points in a phantom by seven operators (four physicians and three non-physicians) were compared using a linear mixed model between the MR guidance and conventional methods using protractors. RESULTS: The average errors of the target locations and needle angles placed using the MR application were 5.9 ± 2.6 mm and 2.3 ± 1.7°, respectively. The average needle insertion error using the MR guidance was slightly smaller compared to that using the conventional method (8.4 ± 4.0 mm vs. 9.6 ± 5.1 mm, p = 0.091), particularly in the out-of-plane approach (9.6 ± 3.5 mm vs. 12.3 ± 4.6 mm, p = 0.003). The procedural time was longer with MR guidance than with the conventional method (412 ± 134 s vs. 219 ± 66 s, p < 0.001). CONCLUSION: MR needle guidance without pre-procedural CT image import is feasible when matching coordinate systems, and the accuracy of needle insertion is slightly better than that of the conventional method.

Isolated endovascular repair of anomalous systemic arterial supply to the left basal lung.

Anomalous systemic arterial supply to the left basal lung is a rare congenital lung malformation, and its optimal treatment strategy is not well defined. We present a case of a 61-year-old man who underwent thoracic endovascular aortic repair (TEVAR) for anomalous systemic arterial supply to the left basal lung complicated with aneurysmal dilatation of the aberrant feeding artery. Computed tomography angiography after TEVAR revealed significant shrinkage of the aneurysmal portion as well as complete occlusion of the aberrant feeding artery. TEVAR proved to be a safe and efficient treatment for this rare arterial abnormality.

A 77-Year-Old Man with a Pulse Granuloma of the Descending Colon Identified by Fluorodeoxyglucose-Positron Emission Tomography (FDG-PET) Imaging 19 Months Following Surgical Resection for Rectal Carcinoma.

BACKGROUND Food particles may sometime lodge in the intestinal wall, resulting in a granuloma. Pulse granuloma is associated with the seed of a legume and has a characteristic appearance on histology. This report describes a case of pulse granuloma of the descending colon identified by fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging. Imaging was done 19 months after surgical resection for rectal carcinoma, and the results of imaging alone suggested a tumor metastasis. CASE REPORT A 77-year-old man underwent sigmoid colostomy for sigmoid colon perforation due to obstruction by rectal cancer affecting the upper rectum approximately 2 years ago. Two months later, after his general condition improved, he underwent laparoscopic low anterior resection. On postoperative pathological examination, the lesion was diagnosed as stage II. Nineteen months later, computed tomography showed an irregular nodule on the dorsolateral side of the descending colon. FDG-PET revealed positive results, and peritoneal dissemination was suspected. Because the lesion was localized and there was no other evidence of metastasis, resection was performed. A pathological examination revealed a pulse granuloma with a central legume seed, and no obvious malignant findings were observed. CONCLUSIONS This report has highlighted the importance of imaging and histopathology in cases in which a solitary nodule is present in the bowel in a patient with previous successful treatment for malignancy. Pulse granuloma, or other types of granuloma associated with impacted food material, may be a cause of a solitary nodule, or pseudotumor, in the bowel wall.

Aortic dissection diagnosed on stroke computed tomography protocol: a case report.

BACKGROUND: Aortic dissection is one of the causes of stroke. Because cerebral infarction with aortic dissection is a contraindication to intravenous recombinant tissue plasminogen activator (rt-PA) therapy, exclusion of aortic dissection is necessary prior to its administration. However, imaging takes time to provide a diagnosis, possibly causing delays in surgical treatment. CASE PRESENTATION: A 65-year-old Japanese female patient was transported to the hospital for a suspected stroke, with back pain and left upper and lower extremity palsy which occurred while eating. Upon arrival at the hospital, the left lower limb paralysis had improved, but the left upper limb paralysis remained. Right back pain had also developed. A plain head computed tomography (CT) scan performed 110 minutes after onset showed no acute bleeding or infarction. Subsequent CT perfusion (CTP) showed acute perfusion disturbance in the right hemisphere without infarction, known as ischemic penumbra. The four-dimensional maximum-intensity projection image reconstructed from CTP showed a delayed enhancement at the right internal carotid and right middle cerebral arteries compared to the contralateral side, suggesting a proximal vascular lesion. Contrast helical CT from the neck to abdomen revealed an acute aortic dissection of Stanford type A with false lumen patency. The dissection extended to the proximal right common carotid artery. The patient underwent an emergency total arch replacement and open stent graft. After recovering well, the patient was ambulatory upon discharge from the hospital. The combination of plain head CT, CTP, and helical CT scan from the neck to abdomen enabled us to evaluate for stroke and aortic dissection within a short amount of time, allowing for early therapeutic intervention. CONCLUSIONS: When acute stroke is suspected due to neurological deficits, plain head CT is the first choice for imaging diagnosis. The addition of cervical CT angiography can reliably exclude stroke due to aortic dissection. CTP can identify ischemic penumbra, which cannot be diagnosed by plain head CT or diffusion-weighted magnetic resonance imaging. These combined stroke CT protocols helped us avoid missing an aortic dissection.

Learning effectiveness of using augmented reality technology in central venous access procedure: an experiment using phantom and head-mounted display.

PURPOSE: Augmented reality (AR) technology improves the learning process in interventional radiology. This study hypothesized that using AR to train for central venous access is superior to using ultrasound alone. METHODS: This study used an AR central venous catheterization phantom with an internal jugular vein (IJV) and subclavian vein (SCV) made of resin body and soft tubing. Ten radiologists attempted to punctuate, using needle placement simulation, under three conditions (ultrasound-, augmented reality-, and ultrasound and AR-guided methods; US-only, AR-only, and US+AR, respectively) using a smart-glass device (HoloLens, Microsoft, Redmond, WA, USA). Subjective (anatomical understanding and self-confidence for procedure) and objective evaluations (optimized needle position and time) were recorded for each condition. RESULTS: The subjective IJV evaluation showed no difference among the guiding methods (p = 0.26 and p = 0.07 for anatomical understanding and self-confidence for procedure, respectively). Conversely, there were significant improvements in subjective and objective evaluations for SCV using the AR-only and US+AR methods (p < 0.05) and US+AR method (p < 0.05), respectively. The AR-only method reduced the time required to fix the needle position to puncture the SCV (p < 0.05), but its objective evaluation did not improve compared with the US-only method (p = 0.20). CONCLUSION: Adding the AR-guided method to the US-guided method improved subjective and objective evaluations in the SVC procedure. The AR technology-assisted training may be more beneficial for use in difficult procedures. Though the AR-only method saved time, no time saving is expected with AR+US method.

[Report in 2018 April ～ 2020 March].

To establish a feasible and practical methodology for harmonization of FDG-PET, we have investigated quantitative physical performance of recent clinical PET scanners (23 scanners) using the NEMA image quality phantom. Compared with the previous phantom data (13 scanners) acquired in the early 2000s, the current phantom data showed better contrasts of small spheres even with a smaller number of coincidence counts. This result suggests that clinical PET image quality and small lesion detectability might have been significantly improved in the past 10 years. Based on the data acquired in this working group, we are planning to update the standard phantom test methodology and harmonizing criteria for FDG-PET.

Computed tomography perfusion in patients of stroke with left ventricular assist device.

Left ventricular assist devices (LVAD) are widely applied for patients with severe heart failure as a bridge to heart transplantation as well as destination therapy. Patients with implanted LVAD have an increased risk of cerebral thrombosis and computed tomographic perfusion (CTP) has the potential to be performed for early diagnosis and treatment of acute ischemic stroke (AIS), including interventional thrombectomy. Here, we report our series of CTP examination in patients having suspected AIS after LVAD implantation. We retrospectively investigated 33 contrast-enhanced CTPs from January 2017 to December 2018 which were performed in 12 cases of patients because of possible neurological findings leading to suspected AIS during LVAD circulatory support who did not have definite ischemic findings nor intracerebral hemorrhage on non-contrast computed tomography. AIS with perfusion disturbance area was diagnosed in 11 (33.3%) out of a total of 33 CTPs in 4 (33.3%) out of 12 patients. Endovascular thrombectomy (EVT) was successfully performed in this research study four times for three patients. CTP was able to detect and determine the indication for EVT without serious complications. CTP could potentially be the first-choice assessment for early diagnosis of AIS with recoverable ischemic penumbra in patients with LVAD implantation.

Safety and feasibility of unilateral double femoral venous access including double sheath insertion via a single-hole method for adrenal venous sampling.

PURPOSE: To assess the safety and feasibility of unilateral double femoral venous access including double sheath insertion via a single-hole method (two-in-one method) for adrenal venous sampling (AVS). MATERIALS AND METHODS: Two 5-Fr sheaths were percutaneously inserted into a single femoral vein for AVS in 324 patients. Two needles were inserted sequentially in tandem under ultrasound guidance; furthermore, two sheaths were individually inserted (two-in-two method) if both punctures were successfully achieved. In the presence of a single puncture, two sheaths were inserted through two guidewires and a temporarily inserted sheath (two-in-one method). This protocol was repeated until two sheaths were successfully inserted. Thus, two sheaths were inserted with the two-in-one method in 56 patients (17.3%) and two-in-two method in 268 patients (82.7%). RESULTS: No significant differences in the technical success rates of AVS were observed (p = 0.067-0.647). Minor groin hematoma was observed more frequently in the two-in-one than in the two-in-two method (8.9% vs. 2.6%, p = 0.039). No major groin hematoma, deep venous thrombosis, or pulmonary embolization was observed. The mean number of needle puncture was 2.5 ± 1.3 and duration of inserting two sheaths 5.1 ± 3.9 min. CONCLUSION: Unilateral double femoral venous access including the two-in-one method is safe and feasible for AVS.

Image quality of early postoperative CT angiography with reduced contrast material and radiation dose using model-based iterative reconstruction for screening of renal pseudoaneurysms after partial nephrectomy.

PURPOSE: To evaluate the image quality of early postoperative CT angiography with low contrast material and radiation dose using model-based iterative reconstruction (FIRST) for screening pseudoaneurysms after partial nephrectomy. METHODS: CT angiography was obtained before surgery using conventional iterative dose reduction reconstruction (AIDR 3D) with 120 kVp and 600 mgI/kg of contrast material and obtained after partial nephrectomy using FIRST with 80-100 kVp and 360 mgI/kg in 35 patients. Contrast-to-noise ratio, visual image quality scores using a 5-point scale, and longest length of the unaffected renal arteries on maximum intensity projection images were retrospectively compared between FIRST and AIDR 3D. RESULTS: No significant differences existed in contrast-to-noise ratio or image quality scores of the renal arteries between FIRST and AIDR 3D (25.8 ± 6.6 vs. 25.4 ± 7.0, p = 0.991 and 4.8 ± 0.4 vs. 4.5 ± 0.9, p = 0.515, respectively). Visualization scores and longest length of the peripheral renal arteries in FIRST were significantly superior to those of AIDR 3D (4.3 ± 0.8 vs. 3.5 ± 1.0, p < 0.001 and 100.4 ± 14.9 mm vs. 90.2 ± 15.7 mm, p = 0.010, respectively). The dose-length product with FIRST was significantly lower than that with AIDR 3D (566.1 ± 217.4 mGy.cm vs. 829.8 ± 324.9 mGy.cm, p < 0.001). CONCLUSION: FIRST can improve visualization of the peripheral renal arteries with contrast material and radiation dose reduced by approximately 30 % compared with AIDR 3D, which enables adequate evaluation of pseudoaneurysms after partial nephrectomy.

Dual-Phase Computed Tomography Angiography Enhances Detection of Contrast Extravasation in Subarachnoid Hemorrhage.

BACKGROUND: Contrast-enhanced computed tomography angiography (CTA) can be used to detect contrast extravasation in intracerebral hemorrhage. However, investigation for contrast extravasation in subarachnoid hemorrhage (SAH) is insufficient. We evaluated the efficacy of dual-phase CTA to improve evaluation of contrast extravasation in SAH. METHODS: We retrospectively evaluated 35 patients with SAH who underwent contrast-enhanced dual-phase CTA within 24 hours from onset. The second-phase scan was performed 8 or 15 seconds following the usual CTA. The frequency of contrast extravasation was compared between phases. We also recorded the time from onset, coma level, interventional treatment, and early mortality. RESULTS: Of 35 patients (22.9%) with SAH, 8 showed contrast extravasation in the second phase compared with 3 in the first phase. Contrast extravasation was correlated with clinical coma level (P < 0.05), and all contrast extravasation was found within 6 hours from onset. Early mortality, treatment decision, and hematoma distribution type did not correlate with existence of contrast extravasation. We also observed 4 cases of secondary subpial hematoma due to SAH, with 3 showing extravasation in both phases. CONCLUSIONS: Dual-phase CTA with a short interval enhances detection frequency of contrast extravasation in SAH and might be a better evaluation tool for SAH.

The effect of scan interval and bolus length on the quantitative accuracy of cerebral computed tomography perfusion analysis using a hollow-fiber phantom.

The shuttle scan technique is expected to extend scan range in cerebral computed tomography (CT) perfusion by 16- or 64-row multidetector CT (MDCT), but it may affect quantitative accuracy. This study aims to evaluate the effect of long scan interval and bolus length on the quantitative accuracy of perfusion indices using an innovative hollow-fiber phantom.We used an originally developed hollow-fiber hemodialyzer covered with polyurethane resin as a perfusion phantom. We scanned the phantom during various scan intervals (1-13 s) and bolus injection lengths (5, 10, 15, and 20 s), and evaluated cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and time-to-peak (TTP). We verified the influence on measured values using a two-way analysis of variance (ANOVA). All measured CBF values were smaller than the theoretical CBF values, and all the measured MTT values were larger that the theoretical MTT values (95% confidence interval). Extended scan intervals resulted in more overestimation of MTT and more underestimation of CBF (p < 0.001). CBV is not affected by the change in scan interval (p < 0.001), and a longer bolus length improved the underestimation of CBV (p < 0.001). Extended scan intervals resulted in the loss of quantitative accuracy in MTT, even with longer bolus injection length, while quantitative CBF values were underestimated and TTP values overestimated. The CBV measurement was not affected by the change in scan interval, and a longer bolus injection improved the accuracy of these measurements.

Mucinous cystic neoplasms in male patients: two cases.

Mucinous cystic neoplasms (MCNs) of the pancreas in male patients are very rare. Though few cases of MCNs in male patients have been reported, it is difficult to reveal them preoperatively. The first patient was a 50-year-old man and was incidentally found to have a cystic mass of 51 mm in the tail of the pancreas. We performed a distal pancreatectomy. The second patient was a 73-year-old man, incidentally found to have a cystic mass of 25 mm in diameter in the tail of the pancreas and a carcinoma of the bile duct. We performed a subtotal stomachpreserving pancreaticoduodenectomy and distal pancreatectomy. In both cases, the cystic lesion was diagnosed pathologically as MCNs. Since MCNs have the risk of malignancy, a resection is recommended. Cases of MCNs in male patients exhibit features that are similar to MCNs in women. We should recognize that MCNs of the pancreas in male patients exists.