Proposal of segmental reading of radionuclide images of the liver

The method of segmental reading of radionuclide images of the liver, which include ordinary (planar) scintigrams as well as SPECT (single photon emission computed tomography) images are presented. Patients showing defects on the liver scan, segments of which have been elucidated by other modalities, were chosen for this study, and the location of defects was assessed in connection with the segment in which they were located. On the basis of this study, the author presents his own segmentation of radionuclide images of the liver. This segmentation seems to be very useful in clinical practice and when applied to ordinary scintigrams, appears to be quite different from the previously published segmentation, which is thought to be partially incorrect.     

钆塞酸二钠增强MRI肝细胞摄取定量参数评估肝功能

目的:探讨钆塞酸二钠(Gd-EOB-DTPA)增强MR扫描中肝细胞分数对肝功能的定量评估价值.方法:2017年8月-2019年1月前瞻性将69例乙型肝炎合并肝硬化的患者纳入本研究.其中肝功能为Child-Pugh A级46例(LCA),Child-Pugh B级(LCB)21例,Child-Pugh C级(LCC)2例...     

Quantitative assessment of para-osteo-arthropathy and its maturation on serial radionuclide bone images.

Paraplegics whose range of motion is limited by para-osteo-arthropathy (POA) may have difficulty in becoming independent unless the heterotopic bone mass is removed. The recurrence rate is high if the bony mass is not mature at the time of surgery. Radiography and alkaline phosphatase correlations are not trustworthy. In 3 paraplegics with POA, radiolabeled osteotropic agents demonstrated a steady decrease in the uptake ratio (heterotopic/normal bone) followed by a steady-state plateau, reflecting the most useful index of maturation and allowing surgical removal of bone without recurrence.     

放射性核素心脏显像对SLE患者的临床应用

目的评价系统性红斑狼疮（ＳＬＥ）患者左心室功能。方法用平衡法门电路心室显像及心肌显像测定２０例正常人和３０例ＳＬＥ患者左室收缩和舒张功能。结果ＳＬＥ患者左室射血分数、相角程、高峰射血率、高峰充盈率分别为０５２±０１１、６０８９±１２１２°、３０８±０４８ＥＤＶ／ｓ和２８８±０４７ＥＤＶ／ｓ；正常对照组分别为０６８±００２、５３２５±５２６°、３６６±０５１ＥＤＶ／ｓ和３３４±０８８ＥＤＶ／ｓ。两组比较，ｔ值分别为４５０、３１１、５８０和４６０，Ｐ均＜００１。阳性率为４８６％，心肌显像阳性率为６４％；放射性核素心脏显像检测ＳＬＥ心肌损害的灵敏度为６３％，特异性为８５％。结论放射性核素心脏显像可以客观评价ＳＬＥ患者左心室功能，对发现ＳＬＥ心肌损害及指导治疗有一定意义。     

81mKr equilibrium radionuclide ventriculography for the assessment of right heart function

Right heart 81mKr equilibrium radionuclide ventriculography was used to derive right ventricular ejection fraction (RVEF) in 12 healthy male volunteers. Anatomical lung subtraction using 99mTc-MAA perfusion scintigraphy was compared with conventional background correction and the effect of imaging projection on the techniques of image analysis evaluated. Both intra and inter observer variability were reduced by anatomical lung subtraction when compared to conventional background correction. In the right anterior oblique (RAO) projection, background corrected RVEF was lower than lung subtracted RVEF - 0.544 +/- 0.05 and 0.612 +/- 0.08 (mean +/- SD) (P less than 0.02). Lung subtracted RVEF in the anterior projection was lower than that with background correction (P less than 0.05) and lower than lung subtracted RVEF in the RAO projection (P less than 0.001). We conclude that optimal separation of right heart structures is achieved in the RAO projection and that reproducibility of the analytical technique is improved by anatomical lung subtraction.     

81mKr equilibrium radionuclide ventriculography for the assessment of right heart function

Right heart^81mKr equilibrium radionuclide ventriculography was used to derive right ventricular ejection fraction (RVEF) in 12 healthy male volunteers. Anatomical lung subtraction using^99mTc-MAA perfusion scintigraphy was compared with conventional background correction and the effect of imaging projection on the techniques of image analysis evaluated. Both intra and inter observer variability were reduced by anatomical lung subtraction when compared to conventional background correction. In the right anterior oblique (RAO) projection, background corrected RVEF was lower than lung subtracted RVEF - 0.544 ±0.05 and 0.612±0.08 (mean ± SD) (P<0.02). Lung subtracted RVEF in the anterior projection was lower than that with background correction (P<0.05) and lower than lung subtracted RVEF in the RAO projection (P < 0.001). We conclude that optimal separation of right heart structures is achieved in the RAO projection and that reproducibility of the analytical technique is improved by anatomical lung subtraction.     

Evaluation of ventricular function with first-pass iridium-191m radionuclide angiocardiography

Iridium-191m would appear to be a highly useful agent for first-pass radionuclide angiocardiography (FPNA), with its very short half-life (4.96 sec), dual photopeaks (65 and 129 keV), and high injectable activity levels (greater than 100 mc). In order to compare 191mIr FPNA to current methods used to define cardiac function, 20 patients referred for cardiac catheterization were studied. Count rate data, right ventricular (RV), and left ventricular ejection fraction (LVEF), LV and diastolic volume (EDV), and end diastolic long axis (AXIS) were evaluated. Count rate data using 191mIr FPNA was consistently better than similar data obtained by 99mTc FPNA. There were acceptable correlations between 191mIr and 99mTc FPNA RVEF (r = 0.848), 191mIr FPNA and contrast angiography LVEF (r = 0.944), LVEDV (r = 0.917), and LV AXIS (r = 0.866). The data thus suggests that 191mIr FPNA has great potential in the evaluation of cardiac function.     

Segmental assessment on ordinary scintigrams and SPECT images of the liver

By examining the area of defect elucidated on the scintigrams and SPECT (single photon emission computed tomography) images, the extension of the tumor into segments was assessed in cases where the SOL (space-occupying lesion) was determined by other methods. In this study, we followed the Couinaud's segmentation. As a result, it was found that the segment with a SOL could be diagnosed fairly well on radionuclide images. Some incorrect assumptions were also found about the segments on ordinary scintigrams in previously published articles. These incorrect assumptions have been accepted for a long time. Although we do not deny that TCT (transmission X-ray computed tomography), echography, angiography, etc. are necessary for a precise judgment on liver segment and also that there are some cases in which the segmental assessment of these radionuclide images is impossible, we do believe that this kind of effort will improve the diagnostic capability of the radionuclide images.     

Segmental assessment on ordinary scintigrams and SPECT images of the liver

By examining the area of defect elucidated on the scintigrams and SPECT (single photon emission computed tomography) images, the extension of the tumor into segments was assessed in cases where the SOL (space-occupying lesion) was determined by other methods. In this study, we followed the Couinaud 's segmentation. As a result, it was found that the segment with a SOL could be diagnosed fairly well on radionuclide images. Some incorrect assumptions were also found about the segments on ordinary scintigrams in previously published articles. These incorrect assumptions have been accepted for a long time. Although we do not deny that TCT (transmission X-ray computed tomography), echography, angiography, etc. are necessary for a precise judgment on liver segment and also that there are some cases in which the segmental assessment of these radionuclide images is impossible, we do believe that this kind of effort will improve the diagnostic capability of the radionuclide images.     

Left ventricular diastolic function in systemic sclerosis: assessment by radionuclide angiography.

The aim of this study was to assess left ventricular function in subjects with systemic sclerosis. Twenty-four women with systemic sclerosis (mean age 48 +/- 11 yr) and 14 age- and sex-matched normal subjects were studied by radionuclide angiography performed at rest with a temporal resolution of 20 msec/frame. Left ventricular volume curves were generated and indices of systolic and diastolic function were computed. Left ventricular diastolic asynchrony was evaluated by dividing the left ventricle into five regions and then computing the time-to-peak filling rate for each region. After excluding the valvular region, the coefficient of variation of this index was obtained. The isovolumic relaxation period was prolonged in systemic sclerosis patients in comparison to normal subjects (127 +/- 39 msec versus 87 +/- 44 msec, p less than 0.05). Moreover, 38% of the systemic sclerosis patients had a subnormal peak filling rate. Left ventricular diastolic asynchrony was increased in the systemic sclerosis group, as expressed by a higher coefficient of variation of the regional time to peak filling rate (27.9% +/- 11.5% versus 14.5% +/- 8.6%, p less than 0.05). Our results indicate an impaired relaxation and an increased diastolic asynchrony in patients with systemic sclerosis.     

A simple filtering routine for radionuclide bone images

The evaluation is carried out of a simple filtering routine for improving the detectability of low contrast lesions in bone scans. With this routine, the unprocessed image is displayed together with three filtered versions, the final decision on the presence of abnormalities being made by comparing the four images. Emphasis is placed on producing a routine which is quick in implementation and, therefore, only small filter arrays are used. Using a routine consisting of a low-pass, a median, and a differential filter, 73% more lesions are detected when the filtered images are also used. The whole routine takes less than 1 min to run.     

Implementation of a digital image superposition algorithm for radionuclide images: an assessment of its accuracy and reproducibility

An operator-interactive algorithm to achieve superposition of organ images has been used with a dedicated nuclear medicine computer system. Its purpose is to achieve organ registration in 128 X 128 digitized images before a direct numerical comparison of the regional distribution of a deposited radiotracer is performed. The accuracy and reproducibility of the algorithm for myocardial images has been tested by four operators, using a set of 28 image pairs in which the relative position of the heart differed by more than 10 mm for each pair. Comparing their results with the known displacements on two occasions provided an assessment of these two important parameters. The accuracy and reproducibility for superposing myocardial images by this digital technique are found to be well within the spatial resolution (FWHM) of the imaging system of the Tl-201 tracer studied.     

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.     

Technique for producing cardiac radionuclide motion images.

Sequential frames of different portions of the cardiac cycle are gated into a minicomputer by using an EKG signal recorded onto digital tape simultaneously with imaging information. Serial display of these frames on the computer oscilloscope or projection of 35-mm half frames of these images provides a cardiac motion image with information content adequate for qualitatively assessing cardiac motion.     

Evaluation of ventricular diastolic function in normal children using equilibrium radionuclide angiography.

Twenty children, aged 10.3 +/- 4.5 (3.3 to 17.5) years, were studied by equilibrium radionuclide angiography to establish a normal range for diastolic parameters. Ejection fraction (EF), peak ejection rate (PER) and time to peak ejection rate (TPER), peak filling rate (PFR) and time to peak filling rate (TPFR) were obtained from ventricular time-activity curves and their first derivative curves, and PFR and TPFR were considered as the diastolic parameters. Normal ranges obtained were as follows: EF, 60 +/- 8%; PER, 3.73 +/- 0.70 EDV-1; TPER, 109 +/- 25 ms; PFR, 3.84 +/- 0.51 EDVs-1; TPFR, 136 +/- 21 ms. There were significant correlations between PER and EF (P less than 0.001), PFR and EF (P less than 0.05), while age and heart rate had no influence upon these variables. Such normal ranges will be useful for evaluation of systolic and diastolic function in children with heart disease.