Embossed x-ray computed tomography utilizing pixel-shifted dual-energy subtraction.

To observe fine blood vessels as uneven tomographic images at a high contrast, we performed tentative experiments on embossed x-ray computed tomography (CT). We constructed a cone-beam CT scanner and carried out dual-energy CT with tube voltages of 60 and 100 kV. X-ray photons penetrating through an object were detected using an indirect-conversion flat panel detector, and radiograms were produced and sent to a personal computer to reconstruct tomograms. Embossed CT was performed using pixel-shifted dual-energy subtraction, and blood vessels filled with Gd medium were observed as uneven images at high contrast and spatial resolutions. Using 1.4-time magnification imaging in combination with a 0.1-mm-focus x-ray tube, the diameter of the object visible on the embossed CT was below 100 µm.

Amyand's Hernia diagnosed preoperatively via a CT scan: A case report.

Amyand's hernia is a rare type of inguinal hernia characterized by the presence of the vermiform appendix within the hernia sac. It was named after Claudius Amyand who performed the world's first successful appendectomy on an 11-year-old boy with a right inguinal hernia in 1735 and discovered a herniated appendix during surgery. This condition warrants urgent surgical treatment, with the type of surgical intervention depending on the appendix's condition. However, the nonspecific clinical presentation often complicates the preoperative diagnosis, emphasizing the critical role of imaging in surgical planning. Herein, we present the case of a 74-year-old male who presented with fever, inguinal swelling, and discomfort. Clinical suspicion of inguinal and scrotal inflammation prompted us to perform a prompt CT scan. This radiological evaluation led to a preoperative diagnosis of a Type 3 Amyand's hernia. This case highlights the significance of CT scans in the accurate and timely diagnosis of Amyand's hernia. Distinguishing between various types of Amyand's hernia is pivotal as it profoundly influences surgical decision-making and postoperative outcomes. By sharing this case, we contribute to current knowledge about Amyand's hernia, increase clinical awareness of the condition, and emphasize the crucial role of imaging in its management.

Validation of a surgical difficulty grading system in laparoscopic cholecystectomy for acute cholecystitis.

BACKGROUND: The surgical difficulty of laparoscopic cholecystectomy (LC) for acute cholecystitis varies from case to case, and appropriate intraoperative evaluation would help prevent bile duct injury (BDI). METHODS: We analyzed 178 patients who underwent LC for acute cholecystitis. Expert surgeons and trainees individually evaluated the surgical difficulty. The inter-rater agreement was analyzed using Conger's κ and Gwet's agreement coefficient (AC). Furthermore, we analyzed the predictive surgical difficulty item for performing subtotal cholecystectomy (STC). RESULTS: Regarding the inter-rater agreement between expert surgeons and trainees, 15 of the 17 surgical difficulty items had a Gwet's AC of 0.5 or higher, indicating "moderate" agreement or higher. Furthermore, the highest and total surgical difficulty scores were deemed "substantial" agreement. Scarring and dense fibrotic changes around the Calot's triangle area with easy bleeding with/without necrotic changes were predictive of whether STC should be performed. CONCLUSIONS: This surgical difficulty grading system is expected to be a tool that can be used by any surgeon with LC experience. STC should be performed to prevent BDI according to the changes around the Calot's triangle area.

Delayed stomach necrosis in a patient with injured celiac artery branches after penetrating abdominal trauma.

Injuries of the celiac artery and its branches are rare, but potentially lethal. Ligation of these arteries is performed to control significant hemorrhage. However, few reports have described the adverse effects of ligating these arteries. A 69-year-old woman with a self-inflicted stab wound was brought to our hospital. Her blood pressure could not be measured, therefore aortic cross-clamping was performed, and epinephrine was administered for resuscitation, an emergency laparotomy was performed, and the roots of splenic artery and common hepatic artery were ligated. The left gastric artery which was anomalous and arose directly from the aorta, was also injured and had to be ligated. Norepinephrine was required after the surgery. Enhanced computed tomography performed on hospital day 4 revealed a disrupted celiac artery. The patient developed gastric necrosis on hospital day 23 and, hence, underwent total gastrectomy was performed. The possibility of delayed stomach necrosis should be considered during the postoperative management of patients who undergo ligation of all of the celiac artery branches and experience global hypoperfusion after the surgery.

Whole cancer-region enhancement using meglumine-gadopentetate-glucose solution and 7.0-T magnetic resonance imaging.

To visualize whole cancerous region including hypoxic cancer without radiation exposure, we developed meglumine-gadopentetate-glucose solution for 7.0-T magnetic resonance imaging. The infusion solution consists of meglumine-gadopentetate and glucose solutions, and these solutions are mixed before the vein drip infusion. We used readily available solutions, and the concentrations of the meglumine-gadopentetate and glucose solutions were 37.14 and 5.0%, respectively. In the first and second experiments, vein infusions were conducted from a rabbit ear using meglumine-gadopentetate-saline and meglumine-gadopentetate-glucose solutions, and T1 weighted imaging was performed to visualize cancerous region. Using the meglumine-gadopentetate saline, it was not difficult to image cancer-growth regions with new blood vessels. Using the meglumine-gadopentetate-glucose solution, the signal intensity of whole cancerous region including hypoxic cancer substantially increased. The visualizing duration for the meglumine gadopentetate glucose was beyond 90 min, and the rabbit survived after the infusion. The signal intensity in the hypoxic cancer was increasing until 90 min using the meglumine-gadopentetate-glucose solution, since the meglumine-gadopentetate molecules were absorbed into almost the whole cancerous region along with glucose-molecule flows.

Investigation of quad-energy high-rate photon counting for X-ray computed tomography using a cadmium telluride detector.

To obtain four kinds of tomograms at four different X-ray energy ranges simultaneously, we have constructed a quad-energy (QE) X-ray photon counter with a cadmium telluride (CdTe) detector and four sets of comparators and microcomputers (MCs). X-ray photons are detected using the CdTe detector, and the event pulses produced using amplifiers are sent to four comparators simultaneously to regulate four threshold energies of 20, 33, 50 and 65keV. Using this counter, the energy ranges are 20-33, 33-50, 50-65 and 65-100keV; the maximum energy corresponds to the tube voltage. We performed QE computed tomography (QE-CT) at a tube voltage of 100kV. Using a 0.5-mm-diam lead pinhole, four tomograms were obtained simultaneously at four energy ranges. K-edge CT using iodine and gadolinium media was carried out utilizing two energy ranges of 33-50 and 50-65keV, respectively. At a tube voltage of 100kV and a current of 60 µA, the count rate was 15.2 kilocounts per second (kcps), and the minimum count rates after penetrating objects in QE-CT were regulated to approximately 2 kcps by the tube current.

Changes in the therapeutic strategy for acute cholecystitis after the Tokyo guidelines were published.

BACKGROUND: This study examined the feasibility of early laparoscopic cholecystectomy (ELC) for acute cholecystitis (AC) according to the Tokyo guidelines severity grade, and analyzed the changes in the therapeutic strategy for AC after the Tokyo guidelines were published. METHODS: A total of 225 patients were enrolled in this study. The therapeutic period was divided into two periods: before and after the publication of the Tokyo guidelines (prior to and including 2007, and from 2008, respectively). RESULTS: Comparing the surgical strategy between ELC and delayed laparoscopic cholecystectomy (DLC), significant differences were found in the length of preoperative hospital stay and total hospital stay for cases of mild AC compared with moderate AC. With conversion to open surgery, postoperative complications including postoperative bile leak were not significantly different. Since ELC was performed significantly more often after publication of the guidelines, preoperative, postoperative, and total hospital stays were significantly shorter in the later period. CONCLUSION: ELC is a safe and effective therapeutic strategy for both mild and moderate AC. The Tokyo guidelines resulted in a significant increase in the performance of ELC and significantly reduced preoperative and total hospital stays without increasing intra- and postoperative complications.

Demonstration of enhanced iodine K-edge imaging using an energy-dispersive X-ray computed tomography system with a 25 mm/s-scan linear cadmium telluride detector and a single comparator.

An energy-dispersive (ED) X-ray computed tomography (CT) system is useful for carrying out monochromatic imaging. To perform enhanced iodine K-edge CT, we developed an oscillation linear cadmium telluride (CdTe) detector with a scan velocity of 25 mm/s and an energy resolution of 1.2 keV. CT is performed by repeated linear scans and rotations of an object. Penetrating X-ray photons from the object are detected by the CdTe detector, and event signals of X-ray photons are produced using charge-sensitive and shaping amplifiers. The lower photon energy is determined by a comparator device, and the maximum photon energy of 60 keV corresponds to the tube voltage. Rectangular-shaped comparator outputs are counted by a counter card. In the ED-CT, tube voltage and current were 60 kV and 0.30 mA, respectively, and X-ray intensity was 14.8 µGy/s at 1.0m from the source at a tube voltage of 60 kV. Demonstration of enhanced iodine K-edge X-ray CT for cancer diagnosis was carried out by selecting photons with energies ranging from 34 to 60 keV.

15Mcps photon-counting X-ray computed tomography system using a ZnO-MPPC detector and its application to gadolinium imaging.

15Mcps photon-counting X-ray computed tomography (CT) system is a first-generation type and consists of an X-ray generator, a turntable, a translation stage, a two-stage controller, a detector consisting of a 2mm-thick zinc-oxide (ZnO) single-crystal scintillator and an MPPC (multipixel photon counter) module, a counter card (CC), and a personal computer (PC). High-speed photon counting was carried out using the detector in the X-ray CT system. The maximum count rate was 15Mcps (mega counts per second) at a tube voltage of 100kV and a tube current of 1.95mA. Tomography is accomplished by repeated translations and rotations of an object, and projection curves of the object are obtained by the translation. The pulses of the event signal from the module are counted by the CC in conjunction with the PC. The minimum exposure time for obtaining a tomogram was 15min, and photon-counting CT was accomplished using gadolinium-based contrast media.

100 µA-100 kV Photon-counting X-ray Computed Tomography System Using an LSO-MPPC Detector and a High-Speed Comparator and its Application to Gadolinium Imaging.

A high-sensitive x-ray computed tomography (CT) system is useful for decreasing absorbed dose for patients, and we performed preliminary experiments for first-generation photon-counting CT using a high-sensitive single detector. X-ray photons are detected using an LSO [Lu2(SiO4)O] single crystal scintillator and a multipixel photon counter (MPPC). The photocurrent from the MPPC is amplified by a current-voltage amplifier and an integrator, and the event pulse is sent to a high-speed comparator. Logical pulses are then produced by the comparator and are counted by a counter card. Tomography is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by the linear scan. The count rate decreased with increase in lower level voltage of the comparator Vl, and the maximum count rate was 265 kcps at a Vl of 0.4 V. The exposure time for obtaining a tomogram was 10 minutes at a scan step of 0.5 mm and a rotation step of 1.0°. The image contrast of gadolinium medium slightly varied with change in Vl. We carried out low-dose-rate photon-counting CT at a tube current of 100 µA and a tube voltage of 100 kV. The energy-dispersive effect of the CT image was confirmed by selecting Vl. The absorbed dose for objects can be reduced using the linear detector consisting of plural LSO-MPPC detectors.

Pancreatic adenosquamous carcinoma presenting as splenic rupture: report of a case.

A 58-year-old female patient presented with the sudden onset of left upper quadrant pain. The physical examination revealed the presence of shock status. Abdominal computed tomography revealed splenomegaly with a huge mass inside the spleen, and massive fluid collection in the abdominal cavity. After splenic artery embolization, laparotomy was performed. The operative findings revealed intra-abdominal hemorrhage and rupture of the lower pole of the spleen. Furthermore, a palpable solid mass was observed at the splenic hilum, and distal pancreatectomy with splenectomy was performed. The macroscopic findings revealed a pancreatic tail tumor at the splenic hilum directly invading the splenic parenchyma. Microscopic examinations showed the tumor to consist of squamous cell carcinoma. Furthermore, old and new thrombi were observed inside small splenic arteries. These findings were considered to represent invasion of pancreatic adenosquamous carcinoma to the spleen, and rupture of the spleen was attributed to splenic ischemia resulting from cancer invasion and splenic vein obstruction.

[Three cases of biliary tract cancer with positive surgical margin obtained a long-term survival after multimodality therapy].

We report three cases of biliary tract cancer with positive surgical margin obtained a long-term survival after multimodality therapy. Case 1: A 58-year-old man had operated PPPD for middle part of biliary tract cancer. Final pathological findings revealed HM2. Hepatic metastasis and anastomotic recurrence were observed, postoperatively. RFA and chemoradiation therapy were performed against these lesions. Nevertheless, the patient died of sepsis associated with hepatic abscess caused by cholangitis 5 years and 10 months after surgery. Case 2: A 72-year-old man had operated for upper part of biliary tract cancer. Intra-operative pathological findings revealed HM 2 and DM 2, extra-bile duct resection was performed for this lesion. After surgery, radiation therapy, systemic chemotherapy and hepatic arterial chemotherapy were performed, nevertheless the patient died of cancer 2 years and 6 months after surgery. Case 3: A 75-year-old man had operated for upper part of biliary tract cancer. Intra-operative pathological findings revealed HM 2 and DM 2, an extra-bile duct resection was performed for this lesion. After surgery, chemoradiation therapy, hepatic arterial chemotherapy and systemic chemotherapy were performed, nevertheless the patient died of cancer 3 years and 6 months after surgery.