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.

Bacteriological analysis of bile in acute cholecystitis according to the Tokyo guidelines.

BACKGROUND: We performed bacteriological analysis of bile in acute cholecystitis (AC) patients graded in severity according to the Tokyo guidelines. METHODS: We enrolled 163 AC patients in whom bacteriological analysis of bile was performed. RESULTS: Significant differences in age (60 vs. 67 years), body temperature (BT) (37.2 vs. 37.6°C), white blood cell count (13,033 vs. 15,177/mm(3)), and serum C-reactive protein (CRP) (8.9 vs. 16.9 mg/dL) were found between the Mild and Moderate severity groups. The prevalence of bactibilia differed significantly between Mild and Moderate patients (45.3 vs. 67.0%, P = 0.0107); however, there were no significant differences in the bacterial strains, prevalence of antimicrobial resistance, or polymicrobial isolation frequency between the 2 groups. Our local antibiogram revealed that several microorganisms showed higher resistance rates; these were also isolated even in Mild cases. Advanced age, high BT, high serum CRP, and presence of marked local infection were identified as being significantly associated with high risk of bactibilia. Receiver operating characteristic curve analysis indicated the optimal cutoff value of age to be 65 years, of BT to be 37.5°C, and of serum CRP to be 13.4 mg/dL. CONCLUSION: Adequate broad-spectrum antimicrobial therapy should be administered perioperatively even for Mild patients classified according to the current Tokyo guidelines. These results suggest that more precise severity grades may need to be established, including age and CRP as additional parameters.

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.

Combined hepatic resection with the inferior vena cava and diaphragm and reconstruction using an equine pericardial patch: report of a case.

We herein report a case of combined hepatic resection with inferior vena cava (IVC) and diaphragm resection, and reconstruction using an equine pericardial patch. A 54-year-old woman showed hepatic cancer recurrence on radiological imaging, with invasion to the caudate lobe of the liver, IVC, diaphragm, and adrenal gland. We resected 10 × 5 cm of the diaphragm. After dissecting the hepatic parenchyma, the caudate lobe was connected only to the IVC. Clamping of the IVC was performed between the IVC below the confluence of the hepatic vein and the suprarenal IVC. A 6 × 3-cm segment of the IVC was then resected. The IVC and diaphragm were reconstructed using an equine pericardial patch, as both defects were too large to repair without a patch. The equine pericardium represents a suitable graft material for repairing both the IVC and diaphragm. Further investigation is needed to determine the durability and anti-infection properties of equine pericardial grafts.

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.

Embossed radiography utilizing energy subtraction.

Currently, it is difficult to carry out refraction-contrast radiography by using a conventional X-ray generator. Thus, we developed an embossed radiography system utilizing dual-energy subtraction for decreasing the absorption contrast in unnecessary regions, and the contrast resolution of a target region was increased by use of image-shifting subtraction and a linear-contrast system in a flat panel detector (FPD). The X-ray generator had a 100-microm-focus tube. Energy subtraction was performed at tube voltages of 45 and 65 kV, a tube current of 0.50 mA, and an X-ray exposure time of 5.0 s. A 1.0-mm-thick aluminum filter was used for absorbing low-photon-energy bremsstrahlung X-rays. Embossed radiography was achieved with cohesion imaging by use of the FPD with pixel sizes of 48 x 48 microm, and the shifting dimension of an object in the horizontal direction ranged from 100 to 200 microm. At a shifting distance of 100 mum, the spatial resolutions in the horizontal and vertical directions measured with a lead test chart were both 83 microm. In embossed radiography of non-living animals, we obtained high-contrast embossed images of fine bones, gadolinium oxide particles in the kidney, and coronary arteries approximately 100 microm in diameter.

X-ray fluorescence camera for imaging of iodine media in vivo.

X-ray fluorescence (XRF) analysis is useful for measuring density distributions of contrast media in vivo. An XRF camera was developed for carrying out mapping for iodine-based contrast media used in medical angiography. Objects are exposed by an X-ray beam from a cerium target. Cerium K-series X-rays are absorbed effectively by iodine media in objects, and iodine fluorescence is produced from the objects. Next, iodine Kalpha fluorescence is selected out by use of a 58-microm-thick stannum filter and is detected by a cadmium telluride (CdTe) detector. The Kalpha rays are discriminated out by a multichannel analyzer, and the number of photons is counted by a counter card. The objects are moved and scanned by an x-y stage in conjunction with a two-stage controller, and X-ray images obtained by iodine mapping are shown on a personal computer monitor. The scan pitch of the x and y axes was 2.5 mm, and the photon counting time per mapping point was 2.0 s. We carried out iodine mapping of non-living animals (phantoms), and iodine Kalpha fluorescence was produced from weakly remaining iodine elements in a rabbit skin cancer.

Multiple necrotic nodules of the liver simulating liver metastasis.

A 70-year-old man was referred to our hospital due to anemia and elevated serum tumor marker levels. He had advanced colon cancer, and hepatic lesions were found incidentally. On ultrasonography (US) and computed tomography (CT), the hepatic lesions had a maximum diameter of 20 mm and were located in Couinaud's segments V, VI, VII, and VIII, which suggested liver metastasis. On early- and late-phase CT during hepatic arteriography (CTHA), all of the lesions had rim enhancement. On early-phase CT during arterioportography (CTAP), all of the lesions were seen as nodules with an irregular perfusion defect, and on late-phase CTAP, all the lesions gradually became iso-dense, and their shape and size changed. Based on the CTAP findings, these lesions were thought to be fibrotic tumors. Partial resection of the liver (including the lesions in Couinaud's segments V and VIII) was done. Histological examination revealed that the lesions were necrotic nodules. Thus, CT angiography (CTHA and CTAP) was useful for identifying necrotic nodules, because their appearance on this modality is different from that of liver metastases.

Single case of renal cell carcinoma and endocrine pancreatic head cancer occurring with von Hippel-Lindau disease.

Von Hippel-Lindau (VHL) disease is an autosomal dominant genetic disease in which various neoplastic lesions occur in multiple organs. Reported here is a case of VHL disease with concurrent renal cell carcinoma and endocrine pancreatic cancer. The patient was a 43-year old woman. On this occasion, the patient had sought treatment from her local physician, complaining chiefly of yellowing of the skin and bulbar conjunctiva. Abdominal ultrasound and computed tomography scans revealed a mass in the right kidney and a mass in the pancreatic head. Peripheral blood genetic analysis revealed an Arg/stop heteroconjugative mutation in codon 113 in exon 1 of the VHL gene on the short arm of chromosome 3 (p25-26). After various tests were performed, the patient was diagnosed with right renal cell carcinoma, malignant tumor of the pancreatic head, and multiple pancreatic cysts accompanying von Hippel-Lindau disease. Right nephrectomy and pancreatoduodenectomy were performed. Based on the histopathological results, the patient was diagnosed with right renal cell carcinoma and highly differentiated endocrine pancreatic cancer. Immunohistologically, a large number of atypical cells were found to be positive for both anti-chromogranin and anti-synaptophysin antibodies in the endocrine tumor. Immunostaining for each type of gut hormone was also performed, but all results were negative. Based on the above findings, nonfunctioning, highly differentiating endocrine cancer was diagnosed. This is the first confirmed case of renal cell carcinoma and endocrine pancreatic cancer occurring concurrently with VHL. This is an important case, so it is presented here along with a short discussion of the literature.

[A case of resectable solitary liver metastasis from breast cancer].

We report a case of resectable solitary liver metastasis from breast cancer. A 53-year-old woman underwent a pectoral muscle-preserving mastectomy for T1 N0M0 (Stage I) left breast cancer in May 2000. Histopathologic diagnosis was medullary carcinoma. Thereafter, the patient was followed up with adjuvant chemotherapy. A solitary tumor in the right lobe of the liver at S6 was found 10 months after mastectomy by ultrasonography. With a diagnosis of liver metastasis from breast cancer, right hepatectomy was performed in May 2001. At present, she remains disease free for 4 years after hepatectomy. We think that a surgical procedure for liver metastasis from breast cancer, if possible, is beneficial in prolonged survival.