The fatal risk in hepatic artery embolization for hemostasis after pancreatic and hepatic surgery: importance of collateral arterial pathways.

PURPOSE: To assess retrospectively the cause of hepatic failure related to hepatic arterial embolization (HAE) for hemostasis after pancreaticoduodenectomy or hepatic lobectomy. MATERIALS AND METHODS: Between June 1993 and March 2006, Twenty HAEs in 17 patients (15 men, two women; mean age, 64 years) were performed. Angiographic findings, including portal vein stenosis, collateral arterial pathways after HAE, and the difference of embolic materials, were recorded. The morbidity (hepatic failure and abscess) and mortality were detailed according to collateral arterial pathways, portal vein stenosis, and embolic material used. RESULTS: Bleeding was controlled in all patients, although two patients required repeat embolization. Hepatic failure (n = 8) and abscess (n = 2) arose in nine of 20 HAEs. Death occurred after six of eight HAEs complicated by hepatic failure. The morbidity and mortality rates of HAE were 45% and 30%, respectively. Hepatic complication was eight times more likely to occur (P = .005) in cases with no hepatic collaterals involving hepatic, replaced, or accessory hepatic arteries. Death was observed only in the cases without hepatic collaterals (P = .011). The correlation between the embolization outcome and the presence of portal vein stenosis or the difference of embolic materials was not significant (P > .61). CONCLUSIONS: HAE can be used to successfully control bleeding secondary to hepatic arterial rupture. In the absence of hepatic collaterals, collateral circulation distal to the occlusion from nonhepatic sources may be inadequate and lead to hepatic failure after HAE.

Bronchial artery anatomy: preoperative 3D simulation with multidetector CT.

PURPOSE: To preoperatively evaluate anatomic variations of the bronchial arteries by obtaining three-dimensional (3D) simulations with multidetector computed tomography (CT). MATERIALS AND METHODS: This study was approved by the institutional review board, and written informed consent was obtained from all participants. Seventy-three consecutive patients with esophageal cancer underwent dynamic multidetector CT. The data were used to generate 3D simulations of the thoracic cavity. These images were then used to evaluate anatomic variations of the bilateral bronchial arteries and the mediastinal course in relation to the esophagus and trachea-bronchi. The preoperative CT findings were correlated with the thoracoscopic findings. RESULTS: CT depicted 118 right bronchial and 105 left bronchial arteries. The right bronchial arteries arose from the intercostal-bronchial trunk (IBT), thoracic aorta, common trunk of both bronchial arteries (CTB), and right subclavian artery in 61, 15, 38, and four cases, respectively, whereas the left bronchial arteries arose from the thoracic aorta, IBT, and CTB in 63, four, and 38 cases, respectively. The right bronchial arteries followed preferential courses through the mediastinum, depending on the parent artery: All 61 right bronchial arteries that arose from the IBT ran along the right side of the esophagus, dorsal to the trachea-main bronchi, whereas the majority of direct-origin and CTB-type right bronchial arteries and all left bronchial arteries ran along the left side of the esophagus. During right thoracoscopy, all bronchial arteries coursing along the right side of the esophagus were identified, whereas those coursing along the left side of the esophagus were frequently out of intraoperative view. Six small right bronchial arteries that were not detected at CT were discovered during surgery. CONCLUSION: Three-dimensional simulation with multidetector CT yields precise preoperative information regarding the anatomy of the bronchial arteries and their variants.

Treatment of in-stent restenosis with beraprost sodium: an experimental study of short- and intermediate-term effects in dogs.

1. The aim of the present study was to evaluate the inhibitory effects of the short-term administration of beraprost sodium, a stable prostaglandin I(2) analogue, on neointimal thickening after stenting. 2. To examine the immediate and short-term effects, Z-stents were placed in the iliac veins of 12 dogs, which were randomly assigned to either a beraprost-treated or control (saline) group. Beraprost (0.35 microg/kg per min) or saline (1.5 mL/min) was administered 30 min before stenting and was continued for 5 h thereafter. Platelet aggregation was measured before and after drug administration. At 3, 7 and 14 days after stenting, dogs were killed and immunohistochemical staining for proliferating cell nuclear antigen was used to quantify the proliferation of vascular smooth muscle cells (SMC). To evaluate intermediate-term effects, a Z-stent was placed in the right iliac vein in 10 dogs, followed by beraprost treatment. Three days later, a second Z-stent was placed contralaterally with saline infusion as a control. After 4 weeks, dogs were killed and neointimal thickness was measured under a light microscope to calculate the intima : media area ratio. 3. Platelet aggregation was more significantly suppressed in the beraprost-treated than in the control group (P = 0.01). In addition, SMC proliferation was significantly lower in the beraprost-treated group 7 and 14 days after stenting (P < 0.05). Over the intermediate term, the intima : media area ratio was significantly lower in the beraprost-treated vein compared with control (P < 0.05). 4. In conclusion, short-term beraprost treatment during stenting suppresses in situ platelet aggregation and SMC proliferation, thus reducing neointimal thickening.

Correct diagnosis of vascular encasement and longitudinal extension of hilar cholangiocarcinoma by four-channel multidetector-row computed tomography.

Accurate diagnosis of local invasion of hilar cholangiocarcinomas is challenging due to their small size and the anatomic complexity of the hepatic hilar region. On the other hand, the correct diagnosis of local invasion is essential for assuring the possibility of curative surgery. The purpose of this study was to evaluate the feasibility of four-channel multidetector-row computed tomography (MDCT) in the assessment of vascular and bile duct involvement, by which we could obtain useful information for the surgical management of hilar cholangiocarcinoma. The subjects were 18 patients for whom the extent of tumor invasion was surgically and pathologically confirmed. All patients underwent preoperative multiphasic CT scanning by MDCT. Arterial and portal dominant phases were acquired using a detector configuration of 1.25 mm X 4 mm, and both axial and multiplanar reconstructed images were interpreted. Longitudinal extension was evaluated up to second-order branches. Vascular invasion is considered to be the degree of tumor contiguity to the hepatic arteries and portal vein and was graded by CT. The longitudinal extension was correctly diagnosed in 14 patients (77.8%). Hepatic artery invasion was correctly diagnosed in 17 patients with sensitivity of 100% and specificity of 90%, respectively. Portal vein invasion was correctly diagnosed in 47 of 51 branches with sensitivity and specificity of 92.3% and 90.2%, respectively. Multiplanar reconstructed images contributed to the correct diagnosis for both vascular encasement and longitudinal tumor extension. In conclusion, MDCT is useful in preoperative evaluation of hilar cholangiocarcinoma, especially when combined with multiplanar reconstructed images.

Perforated and nonperforated appendicitis: defect in enhancing appendiceal wall--depiction with multi-detector row CT.

PURPOSE: To retrospectively evaluate the accuracy of multi-detector row helical computed tomography (CT) with intravenous contrast material and without oral contrast material for depiction of perforated appendicitis. MATERIALS AND METHODS: This study was approved by the institutional review board; informed consent was waived. CT images in 102 patients (60 male patients, 42 female patients; age range, 4-82 years; mean age, 37.3 years) with surgically and pathologically proved appendicitis who were examined between January 2000 and December 2002 were retrospectively reviewed. Original transverse sections at 3- or 2-mm collimation and 1.5- or 1.0-mm intervals were viewed by using cine mode observation. Two independent observers evaluated five specific findings (defect in enhancing appendiceal wall, abscess, phlegmon, extraluminal air, and extraluminal appendicolith). Sensitivity, specificity, and accuracy of the specific findings in the diagnosis of perforated appendicitis were evaluated. RESULTS: Perforated appendicitis was present in 40 patients, and nonperforated appendicitis was present in 62 patients. A defect in the enhancing appendiceal wall was present in 38 patients in the perforated group. Two patients in the nonperforated group had false-positive findings for a defect in the enhancing appendiceal wall. Sensitivity, specificity, and accuracy of this finding in the diagnosis of perforation were 95.0%, 96.8%, and 96.1%, respectively. Sensitivities for abscess, extraluminal air, and extraluminal appendicolith were 37.5%, 22.5%, and 32.5%, respectively. These three findings were not found in patients with nonperforated appendicitis. Phlegmon was seen in 16 patients in the perforated group and in three patients in the nonperforated group. Sensitivity, specificity, and accuracy of phlegmon in the diagnosis of perforation were 40.0%, 95.2%, and 73.5%, respectively. CONCLUSION: Multi-detector row CT allows an accurate (96.1%) diagnosis of appendiceal perforation by the depiction of a defect in the contrast material-enhanced appendiceal wall.

Differentiation of pathologic subtypes of papillary renal cell carcinoma on CT.

OBJECTIVE: We reviewed the CT findings of the subtypes of papillary renal cell carcinoma (RCC), which behave differently clinicopathologically. CONCLUSION: The CT features of the two pathologic subtypes of papillary RCC differ, probably reflecting their different pathologic features. Type 1 tumors have more distinct margins than type 2 tumors and have homogeneous density. Although type 2 tumors in the early stages show findings similar to those of type 1 tumors, they are at more advanced stages on the whole, with CT features showing indistinct margins, frequent centripetal infiltration, and tumor thrombi in all pT3b cases. Radiologists should be familiar with the CT features of papillary RCC that suggest different pathologic behaviors, such as tumor stage, tumor proliferation, and microvascular or vascular invasion.

Validation of the use of calibration factors between the iodine concentration and the computed tomography number measured outside the objects for estimation of iodine concentration inside the objects: phantom experiment.

PURPOSE: The aim of this study was to validate the use of a calibration factor measured outside the object for estimating the iodine concentration inside the object to improve the accuracy of the quantitative contrast-enhanced computed tomography (CT). MATERIALS AND METHODS: Several known concentrations (0, 6, 9, and 12 mg I/ml) of iodine contrast material (CM) samples were placed inside and outside cylindrical acrylic phantoms of two sizes and were imaged under various combinations of the tube voltages and currents (kV/mAs-80/200, 100/200, 120/200, 140/200) to obtain K factors. The K factors were compared between the phantoms and among the tube voltages. Each CM concentration was estimated from the CT number using the K factor measured outside the phantom. RESULTS: The K factors varied between the phantoms or among the tube voltages (P < 0.05). Although there were statistically significant variations in K factors among the different regions in a phantom, the mean variation coefficient was 3%-4%. The mean error of the estimated concentration was -5.5%. CONCLUSION: The CM concentration should be accurately estimated at the region within a patient's body using the K factor measured at the surface of the body regardless of body size and tube voltage.

Ischemic complications associated with resection of opercular glioma.

OBJECT: Opercular glioma inferolateral to the hand/digit sensorimotor area can be resected safely using a neuronavigation system and functional brain mapping techniques. However, the surgery can still sometimes cause postoperative ischemic complications, the character of which remains unclear. The authors of this study investigated the occurrence of infarction associated with resection of opercular glioma and the arterial supply to this region. METHODS: The study involved 11 consecutive patients with gliomas located in the opercular region around the orofacial primary motor and somatosensory cortices but not involving either the hand/digit area or the insula, who had been treated in their department after 1997. Both pre- and postoperative diffusion-weighted magnetic resonance (MR) imaging was performed in the nine consecutive patients after 1998 to detect ischemic complications. All patients underwent open surgery for maximum tumor resection. Postoperative MR imaging identified infarction beneath the resection cavity in all patients. Permanent motor deficits associated with infarction involving the descending motor pathway developed in two patients. Cadaveric angiography showed that the distributing arteries to the corona radiata were the long insular arteries and/or medullary arteries from the opercular and cortical segments of the middle cerebral artery. CONCLUSIONS: Subcortical resection around the upper limiting sulcus of the posterior region of the insula and wide resection in the anteroposterior and cephalocaudal directions of the opercular region were considered to be risk factors of the critical infarction. Surgeons should be aware that resection of opercular glioma can disrupt the blood supply of the corona radiata, and carries the risk of permanent motor deficits.

Virtual CT thoracoscopy: preoperative simulation for thoracoscopic surgery of esophageal cancer.

Thoracoscopic esophageal surgery is a complex procedure requiring simultaneous dissection of the esophagus and lymph nodes while maintaining the surrounding vessels. Because of the difficulty in obtaining comprehensive views of the operative field, three-dimensional (3-D) images with preoperative information on the vascular system, esophagus, trachea, lungs, lymph nodes, skin, and bones would be extremely helpful in performing the surgery.

High-density materials do not always induce artifacts on PET/CT: what is responsible for the difference?

OBJECTIVE: PET/CT often show increased uptake at sites of high-density materials. However, some materials seldom demonstrate increased uptake on PET/CT, such as the materials used in hip prostheses. We hypothesized that the motion of materials may be crucial for such artifacts. Here, we present representative cases, and validate our hypothesis based on the results of phantom studies. METHODS: A standard cylinder, 20 cm in diameter, was filled with approximately 37 MBq of 18F-based activity, and a pacemaker was attached to the side of the cylinder. This phantom was placed on the bed with the pacemaker side facing the scanner. PET scans were performed using a Biograph LSO DUO. CT scans were performed first for transmission scans, followed by acquisition of emission scans. The phantom was first scanned (protocol 1). The phantom was then moved about 2 cm closer to the distal edge of the bed just after transmission CT scan, and the emission scan was performed (protocol 2). RESULTS: Homogenous uptake was seen in the cylinder in protocol 1, and there was no visible uptake at the site of the pacemaker. In contrast, a clear hotspot was seen at the site of the pacemaker in protocol 2. The uptake in the cylinder was inhomogeneous; that on the pacemaker side of the cylinder was low, while that on the opposite side was high. CONCLUSIONS: High-density materials do not show false increased uptake without motion on PET/CT. Motion of these materials surrounded by radioactive organs may play an important role in inducing false increased uptake on PET/CT.

Involvement of pterygoid venous plexus in patulous eustachian tube symptoms.

CONCLUSIONS: The pterygoid venous plexus (PVP) is an important factor in the mechanism of eustachian tube (ET) closure under conditions that can cause increased venous pressure in the head, such as during neck compression and postural change from the sitting/standing to the recumbent position. OBJECTIVES: The symptoms of patulous ET are usually improved by neck compression or postural change (from sitting/standing to recumbent position). Venous congestion around the ET and/or gravitational change may be involved in the changing degree of symptoms, but its mechanism is not understood. This study investigated whether the PVP is involved. MATERIALS AND METHODS: The dimensions of soft tissues surrounding ET were measured on magnetic resonance images before and after neck compression. RESULTS: The lateral pterygoid muscle became enlarged after neck compression. Simultaneously, the volume of venous plexus observed between the medial pterygoid muscle and tensor veli palatini muscle was increased. Such enlargement was probably due to blood pooling in the PVP, resulting in protrusion of the ET anterior wall to the luminal side, and decreased ET patency.

Morphologic analyses of mandible and upper airway soft tissue by MRI of patients with obstructive sleep apnea hypopnea syndrome.

STUDY OBJECTIVES: To evaluate the morphological features of the mandible and the volume of the upper airway soft tissues in determining the anatomical risk factors for the upper airway in Japanese male patients with obstructive sleep apnea hypopnea syndrome (OSAHS). METHODS: Five morphological parameters of the mandible at the mandibular base plane and three volumetric parameters of the upper airway soft tissue were analyzed using three-dimensional (3D) magnetic resonance imaging software in 31 OSAHS and 20 controls. RESULTS: There were no significant differences between the two groups in mandibular internal width (the distance between the internal right and left gonia [IRG and ILG]) and mandibular bony thickness. However, the patients with OSAHS had a significantly wider mandibular divergence (the angle between the spina mentalis (SM)- IRG line and SM- ILG line), a smaller mandibular internal length (the perpendicular distance from SM to the RG- LG line), and a smaller area than the normal subjects at the mandibular base plane. There were no significant differences in these morphological parameters for the mandible between obese and nonobese OSAHS patients. The volumes of the tongue, soft palate, and lateral pharyngeal walls were not significantly different between the OSAHS and the control groups. CONCLUSIONS: Japanese male OSAHS patients had specific anatomical features in the bottom part of the mandible; however, obesity seemed to be a less significant risk factor. Investigators and clinicians must realize that ethnicity may modify the effects of obesity and abnormal craniofacial anatomy as risk factors for the pathogenesis of OSAHS.

Evaluation of the relationship between physiological FDG uptake in the heart and age, blood glucose level, fasting period, and hospitalization.

OBJECTIVE: Positron emission tomography (PET) with fluorodeoxyglucose (FDG) is widely used for evaluation of cancer and ischemic heart disease. Recently, increased myocardial FDG uptake has been reported to be related to some types of heart disease, such as sarcoidosis. However, the physiological increased FDG uptake in the heart often mimics the abnormal high uptake in these cases. In this study, we investigated the relationships between myocardial uptake and age, blood glucose level, fasting period, and hospitalization status (inpatient vs. outpatient). METHODS: A total of 159 non-diabetic patients were enrolled in the present study. Patients were imaged on a PET/CT scanner, and a three-dimensional region of interest (ROI) was drawn on the fused PET/CT image to measure the maximum standardized uptake value (SUV(max)) of the whole left ventricle. RESULTS: No significant relationships were observed between myocardial uptake and age or fasting period. Blood glucose level showed a significant relationship (p = 0.025) with myocardial uptake, but the R-square was extremely small (r2 = 0.03). With an SUV(max) threshold of 3.0, there was no significant difference between inpatients and outpatients. However, outpatients showed a significantly higher frequency of myocardial uptake over SUV(max) of 5.0 (chi2 test: p = 0.046). CONCLUSION: It is difficult to predict the degree of physiological uptake in the heart from data regarding age, fasting period, or blood glucose level. Outpatients tend to show higher myocardial uptake than inpatients, which may make it difficult to detect abnormally increased uptake in the heart. A long fasting period, such as overnight fasting, is an inadequate means to reduce the physiological uptake of FDG in the heart.

FDG PET in solitary metastastic/secondary tumor of the kidney: a report of three cases and a review of the relevant literature.

Metastatic tumors or secondary lymphoma of the kidney are rare and can often be missed on conventional computed tomography (CT) imaging. On the other hand, many types of metastatic tumor or lymphoma can be detected clearly as hotspots of elevated uptake on FDG PET. However, excreted FDG present in the urinary tract mimics these findings and interferes with image reading. Careful investigation of the renal cortex by FDG PET and review of anatomical images, such as the findings of CT and MRI, have important roles in the detection of renal tumor. Here, we present three cases of solitary metastatic/secondary tumor of the kidney, and discuss the features of the lesions on FDG PET in comparison with their appearance on CT.

Surgical treatment of paraventricular cavernous angioma: fibre tracking for visualizing the corticospinal tract and determining surgical approach.

Surgical treatment of deep-seated lesions involving the corticospinal tract is one of the most challenging areas of contemporary neurosurgery, even given the recent development of radiological methods including three-dimensional anisotropy contrast magnetic resonance imaging (MRI) axonography. Fibre tracking using diffusion tensor imaging is another MRI technique that can be used to visualize anisotropy and the orientation of white matter tracts in the brain. We report herein a patient with a paraventricular cavernous angioma manifesting as hemiparesis caused by haemorrhage. Preoperative conventional MRI failed to determine the anatomical relationship between the paraventricular lesion and the corticospinal tract, whereas fibre tracking using free software (dTV for MR-DTI analysis) indicated that the corticospinal tract was displaced anterolaterally from the medial side. The paraventricular lesion was completely removed without damaging the corticospinal tract using a transcortical transventricular approach. Preoperative fibre tracking is useful in surgical planning for procedures involving deep-seated lesions adjacent to the corticospinal tract, and may avoid postoperative morbidity due to corticospinal tract injury.

Atlantoaxial osteoarthritis in rheumatoid arthritis: FDG PET/CT findings.

The cervical spine is a common focus of destruction in patients with rheumatoid arthritis, and the resultant instability and neural compression represent severe complications in these patients. Evaluation of disease activity at the level of the atlantoaxial joint is important in such cases. Here, we report a 47-year-old man with a 3-year history of rheumatoid arthritis. FDG PET/CT clearly demonstrated a hot spot in the atlantoaxial area, suggesting high metabolic activity of synovitis.

Quantitative vascular measurements in arterial occlusive disease.

Accuracy in quantifying arterial occlusive disease requires an understanding of the relevant technical considerations and familiarity with the strengths and weaknesses of various imaging modalities in this setting. The degree of stenosis is evaluated in terms of diameter stenosis, which can be measured on either projection images or cross-sectional images, or area stenosis, which can be measured only on cross-sectional images. With projection images, the minimum luminal diameter should be sought on multiple images obtained at different angles. The reference site used for measurement should be noted and may be located at the level of the lesion or in a normal-looking portion of the stenotic vessel near the lesion. Multi-detector row computed tomographic (CT) angiography and magnetic resonance (MR) angiography are starting to replace digital subtraction angiography in quantifying arterial occlusive disease. CT angiography allows accurate evaluation without reducing in-plane resolution, although beam-hardening artifacts from high-attenuation structures can degrade image quality. MR angiography is useful even in cases of severe calcification but has a lower spatial resolution. Ultrasonography (US) may also be helpful in quantifying arterial occlusive disease; US analysis is almost always based on blood flow velocity measurement. Precise measurements of stenotic occlusion will help determine optimal therapy for affected patients.

The effects of copper-histidine therapy on brain metabolism in a patient with Menkes disease: a proton magnetic resonance spectroscopic study.

We report on metabolic changes in the brain of a boy with Menkes disease. He was treated with parenteral copper (Cu)-histidine supplementation, from 5 months of age, and assessed with proton magnetic resonance spectroscopy ((1)H-MRS). The single-voxel (1)H-MRS before treatment revealed an accumulation of lactate and a reduced N-acetyl aspartate (NAA)/total creatine (tCr) ratio with a z-score of -3.0. During treatment, the lactate signal faded away, whereas the NAA signal gradually increased to a z-score of -1.5 at 120 days of treatment. The choline/tCr ratio did not deviate much initially (z-score +0.5), but the ratio increased markedly during treatment (z-score +4.8). Consequently, the Cu-histidine therapy initiated after the critical period still improved the neuronal metabolism, suggesting that some Cu was delivered to neurons. Nevertheless, the brain atrophy, impaired myelination, and severe neurological symptoms were not ameliorated.