Direct evidence for the location of kallikrein in the striated ducts of the cat''s submandibular gland by the use of specific antibody.

Kallikrein was located in the apical portion of the striated duct cells of the cat's submandibular gland by an immunohistochemical technique. This portion only of these cells showed an intense band of specific fluorescence. There was no evidence of specific fluorescence in the acinar and demilune cells nor in the interstitial tissue or blood besells. In some sections the collecting ducts showed a very fine fluorescent luminal rim.     

Hepatocellular carcinoma: Efficacy of transcatheter oily chemoembolization in relation to macroscopic and microscopic patterns of tumor growth among 100 patients with partial hepatectomy

Purpose: To evaluate the efficacy of transcatheter oily chemoembolization (TOCE) for hepatoceliular carcinoma (HCC) on the basis of microscopic and macroscopic findings postembolization. Methods: HCCs ranging in size from 0.5 to 13 cm (mean 3.6 cm) were obtained from partial hepatectomies of 100 consecutive patients who had undergone TOCE between 20 and 246 days (mean 59.5 days) prior to surgery. The efficacy of TOCE was assessed on the basis of the necrotic to live cell ratio of the tumors. The microscopic pattern of tumor growth was grouped into expanding type (complete capsule formation) and replacing type (incomplete or no capsule). There were five types of macroscopic groupings: single nodule, single nodule with extranodular growth (SNE), contiguous and noncontiguous multinodular, and massive growth type. Results: Among 79 cases with the expanding type, 29 (37%) had 100% HCC necrosis, but none with 100% necrosis were in the replacing type. By macroscopic grouping, the efficacy of TOCE decreased from the single nodule type (50% of patients had 100% necrosis) to the SNE type (21%), and the other types (9%).     

MR appearances of radiofrequency thermal ablation region: histopathologic correlation with dog liver models and an autopsy case

RATIONALE AND OBJECTIVES: The purpose of this study was to evaluate the utility of magnetic resonance (MR) imaging for indicating the extent of true tissue necrosis of the liver after radiofrequency (RF) ablation in comparison with histopathologic findings in dog models and an autopsy case. MATERIALS AND METHODS: RF ablation of the liver parenchyma was performed on three dogs under general anesthesia. MR appearances of the RF-ablated regions on T1-weighted fast-low angle shot (FLASH; repetition time/echo time [TR/TE]/flip angle: 120/3.8/70),T2-weighted turbo spin echo (3000/80/echo train = 25) and contrast-enhanced T1-weighted images were compared with histopathologic findings. An autopsy case with hepatocellular carcinoma was also enrolled in this study. RESULTS: All ablated regions showed three zones on T1-weighted FLASH images: a central zone with low intensity, a broad hyperintense middle zone, and a surrounding hypointense band. The central and middle zones corresponded to the degrees of coagulation necrosis observed during histopathologic examination, whereas no viable cells were seen in these zones during the microscopic examination using nicotinamide adenine dinucleotide diaphorase stain. The surrounding hypointense band corresponded to sinusoidal congestion in the acute phase and to fibrotic change in the subacute phase. CONCLUSION: MR imaging using the FLASH sequence can accurately determine the extent of the necrotic area after RF ablation.     

Detection of hypervascular hepatocellular carcinoma with dynamic magnetic resonance imaging with simultaneously obtained in-phase and opposed-phase echo images

PURPOSE: The technique of double-phase echo chemical shift gradient-echo magnetic resonance (MR) imaging with the fast low-angle shot sequence (double-echo FLASH) provides in-phase and opposed-phase (double-phase) images simultaneously. The purpose of this study was to assess whether the dynamic study with a combination of in-phase and opposed-phase (double-phase) echo images improves the detectability of hypervascular hepatocellular carcinoma (HCC) compared with that with either in-phase or opposed-phase images alone. METHOD: Thirty-seven patients with 107 hypervascular HCCs who underwent the whole-liver double-phase echo dynamic MR imaging were enrolled in the study. Three radiologists blindly read in-phase images alone, opposed-phase images alone, and then double-phase images together. Sensitivity and positive predictive values as well as the areas below the alternative-free response receiver operating characteristic curve (Az values) for each imaging technique were calculated and compared statistically. RESULTS: The mean sensitivity, positive predictive values, and Az values for hypervascular HCCs were 51%, 77%, and 0.52 for in-phase imaging; 55%, 86%, and 0.58 for opposed-phase imaging; and 57%, 84%, and 0.63 for double-phase imaging, respectively. The mean sensitivity for opposed-phase imaging was significantly higher than that for in-phase imaging (P < 0.05), and the mean sensitivity for double-phase imaging was higher than that for in-phase imaging (P < 0.01). The mean Az value for the double-phase imaging was significantly higher than that for in-phase imaging (P < 0.01). CONCLUSION: Dynamic MR imaging with double-phase images was recommended for the detection of hypervascular HCC.     

Effect of superparamagnetic iron oxide on tumor‐to‐liver contrast at T2*‐weighted gradient‐echo MRI: Comparison between 3.0T and 1.5T MR systems

Purpose

To compare 3.0T and 1.5T MR systems in terms of the effect of superparamagnetic iron oxide (SPIO) on tumor‐to‐liver contrast in T2*‐weighted gradient‐echo MRI.

Materials and Methods

SPIO‐enhanced gradient‐echo MR images of the liver with four different TEs (3, 5.3, 6.5, and 8.5 msec) were obtained by means of 1.5T and 3.0T systems. Quantitative analyses of relative signal intensities (SIs) and relative tumor contrast and qualitative analyses of image quality and lesion conspicuity of the liver were performed in 22 patients, 16 of whom had malignant liver tumors.

Results

With both 1.5T and 3.0T, at TE = 8.4 msec, the relative SI of liver and relative tumor contrast were significantly (P < 0.01) lower and higher, respectively, than that for any of the other TEs. There were no significant differences in the relative SI of the liver, relative tumor contrast, image quality, and tumor conspicuity for the same TE between the 1.5T and 3.0T systems.

Conclusion

Our results showed that the effect of SPIO on tumor‐to‐liver contrast at T2*‐weighted gradient‐echo imaging was similar for the 1.5T and 3.0T systems, and that the 8.4‐msec TE was optimal of the four TEs used in this study at 3.0T. J. Magn. Reson. Imaging 2009;29:595–600. © 2009 Wiley‐Liss, Inc.     

Dobutamine-stress electrocardiographically gated positron emission tomography for detection of viable but dysfunctional myocardium

PURPOSE: This study was performed to determine whether low-dose dobutamine stress electrocardiography (ECG)-gated fluorine-18 fluorodeoxyglucose (FDG)-positron emission tomography (PET) can assess wall motion and identify myocardium without contractile reserve despite preserved FDG uptake. METHODS: Fifty-three patients with myocardial infarction and normal sinus rhythm underwent ECG-gated FDG-PET and transthoracic echocardiography. Wall motion of 10 segments of the left ventricle was graded as normal, hypokinetic, or akinetic/dyskinetic. RESULTS: In 365 (76%) of 480 segments, assessment of wall motion was concordant between the 2 modalities. In 30 patients dobutamine-stress ECG-gated FDG-PET was performed. In 13 (50%) of 26 dysfunctional segments with normal FDG uptake, 16 (36%) of 44 dysfunctional segments with mildly reduced FDG uptake and 12 (25%) of 48 dysfunctional segments with moderately reduced FDG uptake, wall motion was improved by dobutamine infusion. CONCLUSION: Assessment of left ventricular wall motion with ECG-gated FDG-PET is feasible, and dobutamine stress ECG-gated FDG-PET can simultaneously identify metabolic viability and contractile reserve.     

Detection of hypervascular hepatocellular carcinoma by dynamic magnetic resonance imaging with double-echo chemical shift in-phase and opposed-phase gradient echo technique: comparison with dynamic helical computed tomography imaging with double arterial phase

PURPOSE: The technique of double-echo chemical shift gradient echo magnetic resonance imaging (MRI) with the fast low-angle shot (double-echo FLASH) sequence provides in-phase and opposed-phase images in a single breath hold. The purpose of this study was to evaluate the efficacy of dynamic MRI with double-echo FLASH imaging for the detection of hypervascular hepatocellular carcinoma by comparing it with dynamic helical computed tomography (CT) imaging with double arterial phase. MATERIALS AND METHODS: Twenty-nine patients with 67 hypervascular hepatocellular carcinoma nodules who underwent both dynamic MRI with double-echo FLASH imaging (repetition time/echo time/flip angle: 160/3.6, 7.0/80 degrees ) and dynamic helical CT imaging with double arterial phase were enrolled in the study. For dynamic MRI, precontrast, arterial, portal venous, and equilibrium phase images were obtained before and approximately 19, 60, and 120 seconds, respectively, after intravenous injection of 0.1 mmol/kg of gadopentetate dimeglumine at a rate of 2 ml/s. For dynamic CT imaging, quadraphase images, including early arterial, late arterial, portal venous, and equilibrium phases, were obtained serially approximately 20, 30, 70, and 180 seconds, respectively, after intravenous administration of 2 ml/kg of 300 mgI/ml of nonionic contrast medium at a rate of 5 ml/s. Three masked observers independently interpreted images obtained with each technique in random order, separately and without patient identifiers. Sensitivity and positive predictive values as well as the area below the alternative-free response receiver operating characteristic curve (Az) for each imaging technique were calculated and compared statistically. RESULTS: Mean sensitivity and positive predictive values of MRI for hypervascular hepatocellular carcinoma were 48% and 94%, respectively, and those of CT imaging were 47% and 91%, respectively. In 11 (38%) of the 29 patients, at least one observer judged dynamic MRI to be superior, whereas in 5 patients (17%), dynamic CT was judged to be superior. There was no significant difference in the sensitivity and positive predictive values between these techniques (p > 0.05). There was no significant difference either in mean Az values between CT (0.55) and MRI (0.57) (p = 0.61). CONCLUSION: Dynamic MRI with double-echo FLASH imaging can detect hypervascular hepatocellular carcinoma as well as dynamic helical CT imaging with double arterial phase.     

Magnetic resonance imaging-guided focused ultrasound ablation of uterine fibroids: early clinical experience

PURPOSE: The aim of this study was to assess the feasibility and effectiveness of magnetic resonance (MRI)-guided focused ultrasound (MRIgFUS) ablation for uterine fibroids and to identify the candidates for this treatment. MATERIALS AND METHODS: A total of 48 patients with a symptomatic uterine fibroid underwent MRIgFUS. The percent ablation volume was calculated, and the patients' characteristics and the MR imaging features of the fibroids that might predict the effect of this treatment were assessed. Changes in the symptoms related to the uterine fibroid were assessed at 6 and 12 months. RESULTS: The planned target zone were successfully treated in 32 patients with bulk-related and menstrual symptoms but unsuccessfully treated in the remaining 16 patients. These 16 patients were obese or their uterine fibroid showed heterogeneous high signal intensity on T2-weighted images. The 32 successfully treated patients were followed up for 6 months. At the 6-month follow-up, bulk-related and menstrual symptoms were diminished in 60% and 51% of patients, respectively. Among them, 17 patients were followed up for 12 months, and 9 of them who showed alleviation of bulk-related symptoms at 6 months had further improvement. The mean percent ablation volume of those nine patients was 51%. In 5 (33%) of the 15 patients with alleviation of menstrual symptoms at 6 months, the symptoms became worse at 12 months. There was a significant difference in the mean percent ablation volume between patients with alleviation of menstrual symptoms and those without (54% vs. 37%; P = 0.03). CONCLUSION: MRIgFUS ablation is a safe, effective treatment for nonobese patients with symptomatic fibroids that show low signal intensity on T2-weighted images. Ablation of more than 50% of the fibroid volume may be needed with a short-term follow-up.     

Non-Hodgkin's lymphoma with Toxoplasma encephalitis]

A 62-year-old man was admitted to our hospital due to fever and systemic lymph-node swelling on June 9, 1998. He was given a diagnosis of non-Hodgkin's lymphoma (diffuse mixed T cell lymphoma) with involvement of mediastinum and para-aortic lymph nodes, pleura, peritoneum, and bone marrow. After diagnosis, combined chemotherapy (CHOP regimen) was started. On day 11, the patient's consciusness level suddenly deteriorated. A brain computed tomographic scan showed no abnormal findings. A cytospin smear of cerebrospinal fluid disclosed tachyzoides (Toxoplasmic bodies), thus yielding a diagnosis of Toxoplasma encephalitis. Oral sulfadoxine pyrimethamine rapidly alleviated the patient's consciousness disturbance. One month later, a cytospin smear and RT-PCR analysis of cerebrospinal fluid detected no tachyzoides. Complete remission of lymphoma was achieved after 2 courses of CHOP therapy. Toxoplasma encephalitis should be considered a potential cause of consciousness disturbance in immunocompromised hosts, such as patients with malignant lymphoma. Cytospin smears of cerebrospinal fluid are a useful tool for the early diagnosis of Toxoplasma encephalitis.