Radial MRI during free breathing in contrast-enhanced hepatobiliary phase imaging.

BACKGROUND: Use of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) for diagnosis of hepatic tumors has been previously reported. Fat-saturated 3D T1-weighted gradient echo sequence (TIGRE) imaging using a breath-hold technique is usually used for dynamic studies and hepatobiliary phase Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI). In cases where the patient has difficulty holding their breath, this scanning method can be difficult. PURPOSE: To investigate the usefulness of a fat-saturated T1-weighted spin-echo (SE) sequence using a radial read-out (radial acquisition regime-SE, RADAR-SE) during free breathing for hepatobiliary phase Gd-EOB-DTPA-enhanced MRI. MATERIAL AND METHODS: Images were acquired at 1.5 T. First, a phantom with diluted Gd-EOB-DTPA was scanned using the TIGRE sequence and the RADAR-SE sequence. Contrast ratios of the sequences were compared. Next, the hepatobiliary phase was imaged in 62 patients using the TIGRE sequence with breath-hold and the RADAR-SE during free breathing. Qualitative and quantitative evaluations were compared. RESULTS: In the phantom study, RADAR-SE had a higher contrast ratio than TIGRE. In the clinical study, artifacts were more conspicuous in RADAR-SE compared to TIGRE images in the qualitative evaluation. However, RADAR-SE images were equal to or better than TIGRE images in patients who had difficulty holding their breath. The signal intensity ratio of the liver was statistically higher using RADAR-SE than TIGRE. CONCLUSION: RADAR-SE can be useful for hepatobiliary phase Gd-EOB-DTPA-enhanced MRI in patients who have difficulty holding their breath.

Factors associated with delayed gastric emptying in patients with stent placement for malignant gastric outlet obstruction.

BACKGROUND AND STUDY AIMS: Delayed gastric emptying (DGE) is an important factor in determining the clinical outcome in patients with stent placement for malignant gastric outlet obstruction but the factors associated with DGE remain unclear. The aim of this study was to investigate whether clinicopathologic data could be used to identify the factors for DGE in such patients. PATIENTS AND METHODS: A prospective, single-arm, observational clinical study was performed in a referral hospital in Japan. A total of 54 patients with stent placement for malignant gastric outlet obstruction were enrolled. A gastric emptying scintigraphy test was performed 1 week after stent placement. The relationship between DGE and clinicopathologic factors was investigated, and also the relationship between DGE and stent patency time, eating period (when the patient was able to maintain oral intake), and survival time. RESULTS: A total of 38.9 % (21 /54) of patients had DGE. The following were identified as independent predictive factors of DGE: opioid use (odds ratio, 5.32; 95 % confidence interval [95 %CI], 1.07 - 26.41; p = 0.04), chemotherapy before stent placement (odds ratio, 8.03; 95 %CI, 1.85 - 34.95; p = 0.006), and smaller stent diameter (odds ratio, 13.59; 95 %CI, 1.72 - 107.41; p = 0.01). No relationship was found between DGE and the level of oral intake, stent patency time, eating period, and survival time. CONCLUSIONS: The factors associated with DGE after stent placement include those associated with the patient's tumor as well as factors relating to their treatment, including stenting. The clinical and functional results after stent placement appear to be unrelated to the gastric emptying findings.

Coronary artery CT low-density plaque area and its ratio to the whole area of a non-calcified plaque at the culprit lesion in patients with unstable and stable coronary artery disease.

Intravascular ultrasound studies have shown that patients with unstable angina pectoris (UAP) more frequently had soft plaques in the culprit coronary arteries than patients with stable angina pectoris (SAP). We evaluated coronary plaque characteristics of culprit lesions in patients with UAP by 64-slice computed tomographic coronary angiography (64-slice CTCA). 64-slice CTCA (Aquilion 64, Toshiba Medical Systems, Otawara, Japan) was performed in 30 patients (UAP = 14, SAP = 16) before percutaneous coronary intervention (PCI). Coronary plaque area was measured by manual tracing for the difference between the area within the external elastic membrane and the area of the vessel lumen at the site of maximal luminal narrowing as observed on a cross-sectional 64-slice CTCA image where PCI was performed. Within this plaque area, CT low-density plaque area (< 50 Hounsfield units) was automatically calculated. There were no differences in stenotic rate and whole plaque area of the culprit lesion between patients with UAP and SAP. However, the CT low-density plaque area was significantly greater in patients with UAP than in those with SAP. A greater area of CT low-density plaque in the culprit lesion is associated with UAP rather than SAP. Measuring CT-low density plaque area on 64-slice CTCA images could be useful for understanding the clinical setting of UAP.

Pediatric high-flow, cervical spinal, macro-arteriovenous fistula, treated with the endovascular cotton candy glue injection technique.

CASE REPORT: A 3-year-old boy presented to our hospital with progressive neurological deficits. Spinal magnetic resonance imaging (MRI) revealed a perimedullary macro-arteriovenous fistula (PMAVF) resulting in a large venous pouch within the parenchyma of the lower cervical spinal cord. Transarterial varix embolization of the fistula from the venous side was performed using N-butyl cyanoacrylate with tantalum powder. Postembolization angiography confirmed obliteration of the fistula, and MRI revealed thrombosis and reduction in size of the venous component. The patient's clinical symptoms were reduced dramatically following the intervention, and no neurological complications occurred due to the treatment. The prognosis of spinal PMAVF depends primarily on the presence of medullar signs and symptoms and on time to treatment. The volume of the venous pouch after the intervention was markedly reduced, and complete clinical recovery was obtained. Urgent endovascular intervention, as seen in this case, is considered first-line therapy and aims to decrease the risk of neurological sequela.

Are there any differences in acute adverse reactions among five low-osmolar non-ionic iodinated contrast media?

OBJECTIVES: The differences regarding adverse reactions in different low-osmolar non-ionic contrast media had not been investigated previously. Thus, the aims of this study were to identify differences in the incidence of adverse reactions in five different low-osmolar non-ionic contrast media. METHODS: We prospectively recorded all adverse events associated with five different low-osmolar non-ionic contrast media used in 8,931 consecutive patients for CT. Patients were randomly assigned to five groups: iomeprol 300 mgI/ml, iopamidol 300 mgI/ml, iohexol 300 mgI/ml, iopromide 300 mgI/ml and ioversol 320 mgI/ml. RESULTS: Adverse events were observed in 241 patients (2.7%). The incidence of acute adverse reactions was significantly higher in the following groups: (1) iomeprol (3.9%) and iopromide (3.5%) groups, (2) patients aged 59 years or less (4.5%) compared with those aged 60 years or over (1.9%), (3) the first period (3.5%) compared with the late period (2.3%), (4) those with a past history of adverse reactions to contrast media (11.2%), and (5) patients receiving contrast media for the first time (3.3%) compared with those had received it previously (2.0%). CONCLUSION: The incidence of acute adverse reactions may be reduced in younger patients by using iopamidol, iohexol and ioversol.

T1-weighted MR imaging of the female pelvis using RADAR-FSE sequence.

Radial scanning is attracting increasing attention as a method of suppressing motion artifacts in magnetic resonance imaging. We compared the effectiveness of radial acquisition regime-fast spin echo (RADAR-FSE), a method of radial scanning, with conventional FSE in the T(1)-weighted imaging setting by scanning Gd-DTPA phantoms and 9 female patients (pelvic imaging). RADAR-FSE suppressed motion artifacts better than FSE but caused streak artifacts and diminished sharpness. Clinicians should be aware of these limitations.

Sporadic gastric neurofibroma underneath early cancer: MDCT gastrography and histological findings.

We report the case of a sporadic gastric submucosal neurofibroma underneath a T1 stage cancer. A 61-year-old man underwent gastroscopy because of epigastralgia and was diagnosed as having T1 stage gastric cancer by an experienced gastroenterologist. Subsequently performed computed tomography (CT) showed poorly circumscribed wall thickening underneath the converged folds on three-dimensional images. On a dynamic enhancement study, the thickened wall was seen to be enhanced gradually from the arterial phase to the equilibrium phase. Based on these findings, we diagnosed stage T2 cancer. Total gastrectomy was performed, and the surgically removed specimen revealed that the wall thickening was caused by a submucosal neurofibroma and that cancer existed in this neurofibroma, invading the submucosa. This patient had no family history of neurofibromatosis, and so the lesion was diagnosed as early gastric cancer with a sporadic submucosal neurofibroma. Coexistence of gastric cancer and a submucosal tumor is rare, but such a case is one of the pitfalls of a CT diagnosis of T stage gastric cancer.

Revisit image control for pediatric chest radiography.

PURPOSE: The aim of this study was to analyze the fraction defectiveness and efficacy of the patient immobilization device (PID) for pediatric chest radiography. MATERIALS AND METHODS: We examined 840 plain chest radiographs in six hospitals, including four children's hospitals and two general hospitals. The mean age of the patients was 1.9 years (range 0-5 years). Two board-qualified pediatric radiologists rated (into three grades, by consensus) the degree of inspiration, rotation, lordosis, scoliosis, and cutoff or coning as well as the quality of the chest radiographs. RESULTS: The incidence of "poor" and "very poor" quality examinations was 2/140 and 3/140 in each of two children's hospitals using PID. The corresponding figures were 9/139 and 17/140 in the two children's hospitals that did not use PID. The general hospital using PID had 14/140 "poor" and "very poor" examinations. The general hospital that did not use PID had 28/140 "poor" and "very poor" examinations. Thus, statistically better quality chest radiography was obtained with the use of PID (P < 0.001). Likewise, rotation, lordosis, and scoliosis were less frequently diagnosed as present when PID was used (P < 0.001, 0.001, 0.05). Cutoff or coning had no relation to the use of PID (P = 0.13). No significant difference was found between the degree of inspiration and the use of PID (P = 0.56). CONCLUSION: Fraction defectiveness in the general hospital that did not use PID was as much as 14 times higher than that of the children's hospitals that used PID. The patient immobilization device is recommended for hospitals with technologists not specifically trained for pediatric examination.

Notes on the application of the Matsui-Kitamura stent-graft for endovascular repair of abdominal aortic aneurysm.

Abdominal aortic and left common iliac aneurysms in a 79-year-old man who had undergone Miles' operation for rectal carcinoma were treated with endovascular repair of an abdominal aortic aneurysm (EVAR), taking into consideration the age, surgical history, and wishes of the patient and his family. The Matsui-Kitamura stent-graft (MK-SG) was designed based on preoperative angiographic mapping. At EVAR, the right leg of the MK-SG was caught at the aortic bifurcation because of unexpected contraction of the MK-SG. To resolve the problem, the body of the MK-SG was dilated with a balloon, slightly lifted while being gradually shortened, and eventually successfully connected to the leg of the MK-SG. Made of nitinol mesh, the MK-SG is stable and flexible enough to make it one of the best stent-grafts for EVAR. A serious drawback, however, is the high contraction rate of the MK-SG itself. It is difficult to estimate the appropriate length of the stent-graft owing to unpredictable contraction. It is important to understand its characteristics and to carefully design and acquire sufficient skills in manipulating MK-SG.

Evaluation of the changes in signals from the spleen using ferucarbotran.

PURPOSE: Because superparamagnetic iron oxide is actively taken into the reticuloendothelial system, the signal intensity observed on T2-weighted images is reduced not only in the liver but also in the spleen. There is no difference in the reduction in signal intensity in the liver after contrast between the ferumoxides and ferucarbotran, but the reduction in signal intensity in the spleen is considerable. In the present study, we examined the efficacy of T2*-weighted imaging to compensate for the reduction in signal intensity in the spleen by administering ferucarbotran. MATERIALS AND METHODS: We examined the images obtained from 35 patients who underwent MRI with ferucarbotran. T2-weighted images and T2*-weighted images were obtained before and after administration of ferucarbotran, and the changes in signal intensity in the liver and spleen were then analyzed. RESULTS: A reduction in signal intensity was observed in the liver by both T2- and T2*-weighted imaging. In the spleen, the signal intensity was reduced on T2-weighted images but was not reduced on T2*-weighted images. CONCLUSION: The reduction in signal intensity due to administration of ferucarbotran is low in the spleen. Thus, it was considered necessary to approach the problem of diagnosing ectopic splenic tissue using ferucarbotran with caution.

Paget's disease of the breast in a woman with neurofibromatosis.

Paget's disease of the breast is a rare and specific type of breast carcinoma in the nipple or areola. On the other hand, neurofibromatosis (NF) is also a rare neurocutaneous disease, which is inherited and affects mainly the skin and the nervous system. In addition, NF is rarely associated with malignant tumors. We present a case of Paget's disease concomitant with NF type 1 in a 66-year-old woman.

Detection of myocardial bridge and evaluation of its anatomical properties by coronary multislice spiral computed tomography.

BACKGROUND: Myocardial bridge (MB) is a common anatomical condition, under which a part of the coronary artery running in the epicardial adipose tissue, is covered with myocardial tissue. It regulates atherosclerosis development and sometimes evokes coronary heart disease through haemodynamic alterations. We attempted to efficiently detect MB and evaluate the anatomical properties of MB by coronary multislice spiral computed tomography (MSCT). METHODS: Sixteen-row MSCT was conducted on 148 patients with coronary heart disease. MSCT images were reconstructed and reformed with transverse scans, curved planar reformat and three-dimensional volume-rendered images. The MB, over 1.0 mm in thickness, was identified by the presence of the "step-down and step-up" appearance. After "trial and error" essays, we could consistently examine the frequency of MB and evaluate the anatomical properties of MB, especially its thickness, together with coronary wall lesions. RESULTS: Twenty-three patients (15.8%) had MB over 1.0 mm in thickness: 21 MBs (87.5%) were located in the left anterior descending artery with a mean thickness and length of 1.8+/-0.7 and 20.0+/-8.6 mm. Moreover, although the tunneled segment beneath MB was always free of coronary wall lesions, 79.2% (19/24) of the segments proximal to MB demonstrated coronary wall lesions. Of special significance were three symptomatic MB patients without any atherosclerotic lesion throughout all the coronary arteries. CONCLUSION: Coronary MSCT is a new imaging technique that provides a non-invasive diagnostic tool for MB and yields much better results of MB detection than previous imaging methods.

Imaging of congenital lipoid adrenal hyperplasia.

This article describes the specific radiological findings of congenital lipoid adrenal hyperplasia (lipoid CAH) in a phenotypic female and karyotypic 46XY infant. Radiological examination showed enlarged bilateral adrenal glands with fatty accumulation and spared medulla. These findings are key to differentiating lipoid CAH from the diseases that cause adrenal insufficiency during early infancy, including other forms of congenital adrenal hyperplasia.

[Use of compressed images for medical checkups: comparison between radiologists' subjective quality assessment and diagnostic usefulness].

With the increasing demand on picture archiving and communication systems (PACS) to handle larger numbers of images, much research has been conducted on the utilization of lossy compression for efficient communication and storage in PACS systems. The receiver operating characteristics (ROC) method is commonly used to determine the appropriate compression ratio of lossy images. However, conducting an ROC experiment is impractical at actual medical facilities because it is difficult to prepare and interpret images with different compression ratios for each modality, body part, and acquisition method. On the other hand, experienced radiologists have the ability to subjectively assess the level of image quality required for interpretatior and quantitative analysis. Therefore, by simply viewing images, they are able to determine the appropriate criteria for image quality and derive a practical compression ratio for each application. The present study focused on lossy compression as employed in teleradiology systems for medical checkups. Experiments comparing radiologists' subjective assessment of compressed images against the diagnostic results obtained using these images were conducted in order to investigate appropriate compression ratios and efficient methods for determining them.

Measurement of visceral fat/subcutaneous fat ratio by 0.3 tesla MRI.

PURPOSE: Visceral fat-type obesity is known to be closely related to hyperlipidemia and diabetes. The visceral fat area/subcutaneous fat area ratio is used for the diagnosis of visceral fat-type obesity. In this study, we measured the visceral and subcutaneous fat areas in the fat images obtained using 0.3 Tesla open-type MRI, and investigated their usefulness. MATERIALS AND METHODS: A short TR was set to shorten the acquisition time, and in-phase and out-of-phase images were acquired during holding of breath. The visceral and subcutaneous fat areas were automatically measured from the fat image using a workstation. The measurements were compared with the visceral and subcutaneous fat areas measured by CT as the gold standard. RESULTS: No major differences were observed in the fat areas measured by MRI and CT. This method was capable of imaging during holding of breath, and clearly imaged visceral and subcutaneous fat. CONCLUSION: CT is not free from the concern of radiation exposure, whereas MRI is free from radiation. For measurement of the visceral and subcutaneous fat areas, 0.3 Tesla MRI was useful.

The diagnosis of lung cancer using 1064-nm excited near-infrared multichannel Raman spectroscopy.

PURPOSE: Raman spectroscopy is based on Raman scattering of light from molecules. Because the wavelength of Raman scattered light depends on molecular composition, Raman spectra provide highly useful information about molecular composition. It has already been shown that Raman spectroscopy is potentially useful for the clinical diagnosis of malignant tumors. However, this technique had never been applied to the diagnosis of lung cancers, primarily because of interference from the strong fluorescence emitted from lung tissues. Our purpose was to examine the effectiveness of near-infrared Raman spectroscopy for the diagnosis of lung cancers. METHODS: We constructed a new near-infrared multichannel Raman system that is capable of measuring high signal-to-noise ratio, fluorescence-free Raman spectra of lung tissues within a measurement time of 1 second. Using this system, we collected a total of 210 Raman spectra from cancerous and non-cancerous lung tissues and analyzed these spectra by a least-squares fitting procedure for cancer diagnosis. RESULTS: The resultant sensitivity of cancer prediction was as high as 91%, with 97% specificity and an error margin of p<0.0001 according to Fisher's exact test. CONCLUSIONS: A method of diagnosing lung cancer efficiently and objectively using Raman spectroscopy has thus been established.

Pulmonary hilar lymph nodes in lung cancer: assessment with 3D-dynamic contrast-enhanced MR imaging.

PURPOSE: We performed 3D-dynamic MRI on patients with primary lung cancer to identify its usefulness for detecting hilar adenopathy shown at surgery. METHODS AND MATERIALS: 30 consecutive patients with peripheral lung cancer underwent preoperative 3D-dynamic Gd-DTPA-enhanced MRI. Two thoracic radiologists blinded to histopathologic findings reviewed those studies independently for hilar adenopathy visualization. The results were correlated with surgical and histopathologic findings. Interreader agreement for the detection of hilar adenopathy was assessed by means of the kappa statistic. RESULTS: Dynamic MRI demonstrated hilar adenopathy, with or without metastasis revealed at surgery, in all of 15 patients. Adenopathy without metastasis was shown in four patients. Dynamic MRI also revealed metastatic adenopathy in 11 of 12 patients with pathologically proven metastasis. There was only one case with lymph node metastasis that did not have adenopathy either on MRI or even at surgery. The diagnostic accuracy of dynamic MRI for adenopathy with or without metastases revealed at surgery were as follows; sensitivity, 100%; specificity, 100%; positive predictive value, 100%; and negative predictive value, 100%, respectively. The diagnostic accuracy of dynamic MRI for hilar lymph nodes metastasis were as follows; sensitivity, 92%; specificity, 78%; positive predictive value, 73%; and negative predictive value, 93%. Interreader agreement was substantial (kappa=0.73) for detection of hilar adenopathy. CONCLUSION: Hilar adenopathy on 3D-dynamic MRI correlated well with that of surgical finding on patients with primary lung cancer. It may have the potential to make an accurate preoperative evaluation of hilar lymph node metastasis from lung cancer.