Immunologic tolerance maintained by CD25+ CD4+ regulatory T cells: their common role in controlling autoimmunity, tumor immunity, and transplantation tolerance

There is accumulating evidence that T-cell-mediated dominant control of self-reactive T-cells contributes to the maintenance of immunologic self-tolerance and its alteration can cause autoimmune disease. Efforts to delineate such a regulatory T-cell population have revealed that CD25+ cells in the CD4+ population in normal naive animals bear the ability to prevent autoimmune disease in vivo and, upon antigenic stimulation, suppress the activation/proliferation of other T cells in vitro. The CD25+ CD4+ regulatory T cells, which are naturally anergic and suppressive, appear to be produced by the normal thymus as a functionally distinct subpopulation of T cells. They play critical roles not only in preventing autoimmunity but also in controlling tumor immunity and transplantation tolerance.

Immunologic self tolerance maintained by T-cell-mediated control of self-reactive T cells: implications for autoimmunity and tumor immunity

T-cell-mediated dominant control of self-reactive T cells is one mechanism for maintaining immunologic self tolerance. It also hampers the generation of immunity to autologous tumor cells. Abrogation of the control can evoke potent tumor immunity as well as autoimmunity in normal animals. This common regulatory mechanism for autoimmunity and tumor immunity can be exploited to devise a novel immunotherapy against cancer.

Immunologic tolerance maintained by CD25+ CD4+ regulatory T cells: their common role in controlling autoimmunity, tumor immunity, and transplantation tolerance

There is accumulating evidence that T-cell-mediated dominant control of self-reactive T-cells contributes to the maintenance of immunologic self-tolerance and its alteration can cause autoimmune disease. Efforts to delineate such a regulatory T-cell population have revealed that CD25+ cells in the CD4+ population in normal naive animals bear the ability to prevent autoimmune disease in vivo and, upon antigenic stimulation, suppress the activation/proliferation of other T cells in vitro. The CD25+ CD4+ regulatory T cells, which are naturally anergic and suppressive, appear to be produced by the normal thymus as a functionally distinct subpopulation of T cells. They play critical roles not only in preventing autoimmunity but also in controlling tumor immunity and transplantation tolerance.

Unusual early bile excretion from the liver in patients with fulminant hepatic failure as detected by Tc-99m-PMT hepatobiliary scintigraphy; Comparison with Tc-99m-GSA scintigraphy

In two females (58 and 14 years old) with fulminant hepatic failure, Tc-99m-PMT hepatobiliary scintigraphy was used to evaluate intrahepatic bile stagnation, and Tc-99m-GSA scintigraphy to evaluate hepatic functional reserve. In both patients, Tc-99m-PMT hepatobiliary scintigraphy showed unusual early bile excretion into the extrahepatic bile duct and small intestine within the first 30 min of imaging. These findings contradicted typical findings of intrahepatic bile stagnation of fulminant hepatic failure. The receptor index and blood clearance index determined from dynamic acquisition data on Tc-99m-GSA scintigraphy suggested a markedly decreased hepatic functional reserve. These findings were compatible with fulminant hepatic failure. A discrepancy was observed between the findings of hepatobiliary scintigraphy and those of Tc-99m-GSA scintigraphy. The pathological state of early bile excretion from the liver into the bile duct should be considered in fulminant hepatic failure.

Naturally anergic and suppressive CD25(+)CD4(+) T cells as a functionally and phenotypically distinct immunoregulatory T cell subpopulation

A CD4(+) T cell subpopulation defined by the expression levels of a particular cell surface molecule (e.g. CD5, CD45RB, CD25, CD62L or CD38) bears an autoimmune-preventive activity in various animal models. Here we show that the expression of CD25 is highly specific, when compared with other molecules, in delineating the autoimmune-preventive immunoregulatory CD4(+) T cell population. Furthermore, although CD25 is an activation marker for T cells, the following findings indicate that immunoregulatory CD25(+)CD4(+) T cells are functionally distinct from activated or anergy-induced T cells derived from CD25(-)CD4(+) T cells. First, the former are autoimmune-preventive in vivo, naturally unresponsive (anergic) to TCR stimulation in vitro and, upon TCR stimulation, able to suppress the activation/proliferation of other T cells, whereas the latter scarcely exhibit the in vivo autoimmune-preventive activity or the in vitro suppressive activity. Second, such activated or anergy-induced CD25(-) spleen cells produce various autoimmune diseases when transferred to syngeneic athymic nude mice, whereas similarly treated normal spleen cells, which include CD25(+)CD4(+) T cells, do not. Third, upon polyclonal T cell stimulation, CD25(+)CD4(+) T cells express CD25 at higher levels and more persistently than CD25(-)CD4(+) T cell-derived activated T cells; moreover, when the stimulation is ceased, the former revert to the original levels of CD25 expression, whereas the latter lose the expression. These results collectively indicate that naturally anergic and suppressive CD25(+)CD4(+) T cells present in normal naive mice are functionally and phenotypically stable, distinct from other T cells, and play a key role in maintaining immunologic self-tolerance.

Abnormal pulmonary accumulation of indium-111 chloride in pneumocystis carinii pneumonia as detected by bone marrow scintigraphy

PURPOSE

Unusual pulmonary uptake of In-111 chloride in a patient with Pneumocystis carinii pneumonia and autoimmune hepatitis is described.

METHOD

In-111 chloride bone marrow scintigraphy was performed to evaluate the bone marrow activity associated with pancytopenia in a 56-year-old woman with autoimmune hepatitis.

RESULTS

An In-111 chloride bone marrow scan showed increased pulmonary uptake predominantly in both upper lung fields. P. carinii pneumonia was seen to be developing as an immunocompromised complication after treatment for autoimmune hepatitis.

CONCLUSION

When In-111 chloride bone marrow scintigraphy shows increased uptake in the lungs of immunocompromised patients, a combined opportunistic inflammatory disease such as P. carinii pneumonia should be considered in the diagnosis.

Implementation and quantitative evaluation of analytical methods for attenuation correction in SPECT: a phantom study

Three differing exact methods of inverting the two-dimensional (2D) exponential Radon transform were implemented and evaluated quantitatively with a phantom study. The phantom had the shape of a pie-chart divided into six cavities, each 480 ml in volume and 10 cm in height, that were symmetrically positioned in a cylinder that was 20 cm in diameter and 10 cm in height. This phantom tests for linearity between true activity concentration and measured activity concentration, and it is denoted as a linearity phantom in the present study. Each cavity contained a different concentration of a homogeneous solution of 99mTc (74, 148, 222, 296, 370 and 444 kBq ml(-1)). Data acquisition was performed with two energy windows: a 20% photopeak energy window set symmetrically over the 140 keV of 99mTc and a secondary 5% energy window set over the 122 keV peak. We optimized a triple-energy window scatter correction method for a gamma camera-collimator system to obtain accurate scatter-corrected projections. A circular ROI 3 cm in diameter was identified over each cavity region, and count density (counts per pixel) was calculated. This value was converted to activity concentration (kBq ml(-1)) using a cross-calibration coefficient between SPECT counts and the gamma well counter. The relation between true activity (x) and measured activity concentration (y) was fitted to a line using the least-squares method. Regression lines were y = 0.63 + 1.0255x (R2 = 0.9987), y = -2.62 + 1.0278x (R2 = 0.9995), and y = 0.092 + 1.0241x (R2 = 0.9989) for the Bellini, Inouye and Metz-Pan methods respectively. In another phantom study using two different types of phantoms, contrast of a cold region in the two was 96% and 101% for all three methods. Combined optimized scatter correction and analytical attenuation correction methods achieve good accuracy in quantification of activity distribution with a uniform attenuating medium.

Thymus and autoimmunity: production of CD25+CD4+ naturally anergic and suppressive T cells as a key function of the thymus in maintaining immunologic self-tolerance

This study shows that the normal thymus produces immunoregulatory CD25+4+8- thymocytes capable of controlling self-reactive T cells. Transfer of thymocyte suspensions depleted of CD25+4+8- thymocytes, which constitute approximately 5% of steroid-resistant mature CD4+8- thymocytes in normal naive mice, produces various autoimmune diseases in syngeneic athymic nude mice. These CD25+4+8- thymocytes are nonproliferative (anergic) to TCR stimulation in vitro, but potently suppress the proliferation of other CD4+8- or CD4-8+ thymocytes; breakage of their anergic state in vitro by high doses of IL-2 or anti-CD28 Ab simultaneously abrogates their suppressive activity; and transfer of such suppression-abrogated thymocyte suspensions produces autoimmune disease in nude mice. These immunoregulatory CD25+4+8- thymocytes/T cells are functionally distinct from activated CD25+4+ T cells derived from CD25-4+ thymocytes/T cells in that the latter scarcely exhibits suppressive activity in vitro, although both CD25+4+ populations express a similar profile of cell surface markers. Furthermore, the CD25+4+8- thymocytes appear to acquire their anergic and suppressive property through the thymic selection process, since TCR transgenic mice develop similar anergic/suppressive CD25+4+8- thymocytes and CD25+4+ T cells that predominantly express TCRs utilizing endogenous alpha-chains, but RAG-2-deficient TCR transgenic mice do not. These results taken together indicate that anergic/suppressive CD25+4+8- thymocytes and peripheral T cells in normal naive mice may constitute a common T cell lineage functionally and developmentally distinct from other T cells, and that production of this unique immunoregulatory T cell population can be another key function of the thymus in maintaining immunologic self-tolerance.

[Time-resolved three-dimensional contrast-enhanced MR angiography of the carotid artery]

Contrast-enhanced MR angiography (ceMRA) allows practical carotid arteriography without venous enhancement. However, it requires some intricate preparation such as a test bolus of the contrast agent or determination of the tracking volume even in the automatic triggering Smartprep system. The purpose of this study was to obtain carotid ceMRA without any preparation by means of a repeated multiple ultrashort three-dimensional MRA sequence (e3d56), i.e., time-resolved MRA (trMRA). Twenty-three patients underwent sagittal trMRA using a 1.0-Tesla superconducting unit. Multiple projection angiograms are acquired in three contiguous phases with a time resolution of 6 seconds per slab, including 10 partitions, after a bolus injection of 10 ml of Gd-DTPA followed by 20 ml of saline at 2 ml/sec. In all patients, the signal from the arteries could be separated from that of the veins in at least one phase. Carotid trMRA with 6-sec temporal resolution is a reliable technique for selective arteriography, avoiding the necessity of timing the contrast agent bolus.

[Serial hepatic and splenic volumetry in acute severe hepatitis]

In this study, we elucidate a relationship between final outcome and changes in hepatic and splenic volume in patients with acute severe hepatitis. The subjects were 40 patients: 10 with sever acute hepatitis (prothrombin time < 40%) and 30 with fulminant hepatic failure (acute type in 12 and subacute type in 18). Liver and spleen volume were measured by CT initially on hospitalization and subsequently 1 to 40 days after hospitalization, and the scans were analyzed retrospectively. Liver volume decreased in 15 of 26 survivors, and all 14 non-survivors. Among 15 survivors and 14 non-survivors whose liver volume decreased, spleen volume increased in none of the survivors, whereas it increased in 11 of the 14 non-survivors. In survivors there was a close parallelism between changing rates of the liver volume and that of the spleen volume (r = 0.82, p < 0.0001). These observations suggest that the decrease of liver volume accompanied by that of spleen volume implies a good prognosis, while the decrease without such accompaniment implies a bad prognosis.

[Effect of the skull on brain perfusion SPECT imaging]

Because attenuation gradually decreases reconstructed counts from the periphery to the center portion of the object, the deep region far from the detector is not clearly observed if attenuation is not compensated. In brain perfusion SPECT, diagnosis is sometimes made using filtered back projection images without attenuation compensation (FBP). Brain perfusion SPECT has the unique characteristic that the radiopharmaceutical accumulates only within the brain and is never taken up by the surrounding skull. This study investigated the effect of skull on brain perfusion SPECT reconstructed with FBP. We theoretically derived the relation between the counts of brain and the linear attenuation coefficient of skull. It was found that the difference in reconstructed counts between the deep gray matter and peripheral gray matter decreased due to the existence of the skull. This result indicated that the deep gray matter was inclined to be visible if the FBP images were displayed according to relative counts normalized to the maximum count of each image. In order to confirm this, we made a numerical phantom with realistic human brain and skull contours on the basis of MR images from a normal volunteer. The linear attenuation coefficient of brain was assumed to be 0.15 cm-1, while that of skull was assumed to be 0.26 cm-1 (denoted as BONE+) or 0 cm-1 (BONE-). In accordance with the theoretical results, the deep gray matter of BONE+ images was more clearly observed than that of BONE- images, if these were displayed using the relative counts of each images. The physical phantom experiments also supported the theoretical and numerical phantom studies.

Immunologic self-tolerance maintained by CD25+CD4+ naturally anergic and suppressive T cells: induction of autoimmune disease by breaking their anergic/suppressive state

Elimination of CD25+ T cells, which constitute 5-10% of peripheral CD4+ T cells in normal naive mice, leads to spontaneous development of various autoimmune diseases. These immunoregulatory CD25+CD4+ T cells are naturally unresponsive (anergic) in vitro to TCR stimulation, and, upon stimulation, suppress proliferation of CD25-CD4+ T cells and CD8+ T cells. The antigen concentration required for stimulating CD25+CD4+ T cells to exert suppression is much lower than that required for stimulating CD25-CD4+ T cells to proliferate. The suppression, which results in reduced IL-2 production by CD25-CD4+ T cells, is dependent on cellular interactions on antigen-presenting cells (and not mediated by far-reaching or long-lasting humoral factors or apoptosis-inducing signals) and antigen non-specific in its effector phase. Addition of high doses of IL-2 or anti-CD28 antibody to the in vitro T cell stimulation culture not only breaks the anergic state of CD25+CD4+ T cells, but also abrogates their suppressive activity simultaneously. Importantly, the anergic/suppressive state of CD25+CD4+ T cells appeared to be their basal default condition, since removal of IL-2 or anti-CD28 antibody from the culture milieu allows them to revert to the original anergic/suppressive state. Furthermore, transfer of such anergy/suppression-broken T cells from normal mice produces various autoimmune diseases in syngeneic athymic nude mice. These results taken together indicate that one aspect of immunologic self-tolerance is maintained by this unique CD25+CD4+ naturally anergic/suppressive T cell population and its functional abnormality directly leads to the development of autoimmune disease.

[MR cholangiopancreatography of Mirizzi syndrome and Lemmel syndrome]

The purpose of this study is to evaluate the usefulness of MR cholangiopancreatography (MRCP) in diagnosing Mirizzi syndrome and Lemmel syndrome. MRCP could show compressed common hepatic duct by enlarged gallbladder in Mirizzi syndrome. Periampulary duodenal diverticulum and compressed lower bile duct can be recognized clearly by MRCP after secretin stimulation. So MRCP should apply for diagnosing of Mirizzi syndrome or Lemmel syndrome.

[Combined scatter and attenuation correction for 201Tl myocardial perfusion SPECT using OS-EM algorithm]

There are two possible ways to obtain scatter-corrected images with the ML-EM (maximum likelihood expectation maximization) algorithm: one is the subtraction of scatter estimate si from projection data pi, and then (pi-si) is used for scatter-corrected projection data (denoted as SC(T)); the other method is the addition of scatter estimate si to the projections calculated from the reconstructed image without performing data subtraction (SC(E)). This paper investigated these two ML-EM algorithms of combined scatter and attenuation correction on 201Tl myocardial perfusion SPECT imaging. Scatter windows were placed one full width at half maximum (FWHM) below and above the photopeak centerline. The scatter fraction in the primary peak was estimated using trapezoidal approximation by the triple energy window method. Phantom and clinical images were reconstructed using 6 iterations of ordered subsets EM algorithm (OS-EM). A cylindrical phantom with a cold-rod insert and a heart/thorax phantom with liver insert were used to evaluate scatter and the attenuation compensation technique. A cylindrical phantom filled with uniform 201Tl solution was used to evaluate statistical noise. The percent root-mean-square uncertainty (%RMSU) was used as a quantitative measure of noise amplification. %RMSU showed that the SC(E) method amplified noise less in comparison with the SC(T) method, however, no significant difference in image quality was observed between the two methods. In conclusion, both the SC(T) and SC(E) methods provided significant and similar improvement in the removal of scatter in 201Tl myocardial perfusion SPECT imaging.

[MR cholangiopancreatography of pancreas divism and anomalous arrangement of the pancreaticobiliary ducts]

The purpose of this study was to evaluate the usefulness of MR cholangiopancreatography (MRCP) for pancreas divism and anomalous arrangement of pancreaticobiliary ducts (APBD). In 214 patients, MRCP was performed. In 204 patients (94%), pancreaticobiliary ductal junction could be recognized. Pancreas divism was observed in 13 of 204 patients (6%), and APBD was observed in 10 of 204 patients (5%). Dynamic MRCP after secretin stimulation was useful for diagnosing pancreas divism and APBD.

[Breath-hold 3D MR urography with 2 ml Gd-DTPA injection]

Breath-hold gadolinium-enhanced 3D MR urography was performed in five healthy volunteers. Enhanced 3D fast gradient-echo with a spectral IR pulse sequence was used for depicting MR urography, which was obtained 5-10 minutes after the injection of 2 ml of gadopentate dimeglumine (0.013-0.02 mmol/kg). The urinary tract was depicted as a high-signal intensity area, and detectability of the non-dilated urinary tracts was superior to that of heavy T2-weighted images. At the same time, comparison between the urinary tract and vascular structure could be made using breath-hold contrast-enhanced 3D MR angiography with an additional Gd-DTPA injection.

[Arterial infusion chemotherapy with SMANCS-Lipiodol for multiple hepatocellular carcinoma]

Fifty-five patients with hepatocellular carcinoma were treated with oily anticancer agent SMANCS dissolved in Lipiodol (SMANCS-LPD). The local response rate after the first arterial infusion in all patients was 39%, against 63% in 27 patients with Lipiodol accumulation occupying more than two thirds of tumor areas. The infusion therapy with SMANCS-LPD is adapted for a vascular-rich hepatocellular carcinoma. An infusion of 4 mg of SMANCS was ineffective for patients with tumors distributing in bilateral lobes of liver. Thus, an increase of infusion dosage or repeated infusions were recommended for such cases.

[Preoperative evaluation of the limitation of hepatic resection using 99mTc-GSA (galactosyl human serum albumin) scintigraphy]

Preoperative evaluation of the operative indication of hepatic resection using the parameters obtained by 99mTc-GSA scintigraphy has been done. In particular, the accurate evaluation of the postoperative hepatic functional reserve essentially depends on these parameters. In the present study, a preoperative evaluation of postoperative hepatic functional reserve using 99mTc-GSA scintigraphy was performed in our operated cases retrospectively.

PATIENTS AND METHODS

Thirty-eight patients who underwent hepatic resection were studied on 99mTc-GSA scintigraphy before and after operation. These patients were divided into two groups. Group A; had no postoperative complications (n = 31). Group B; had some postoperative complications (n = 7). Preoperative parameters of 99mTc-GSA liver scintigraphy (HH15, LU15) were calculated from the activities of liver and cardiac ROIs at 5 and 15 minutes after injection. The resection ratio (RR) was obtained by comparing the liver volumes which were calculated from the pre- and postoperative SPECT studies. The resectability indices (Res) were as follows: Res (LU15) = LU15 x (100-RR(%)/100, Res (HH15) = (1/HH15) x (100-RR (%)/100.

RESULTS

There were statistically significant differences in the distribution of Res between A and B groups (p = 0.002, Mann-Whitney test). The values of Res, of which half of patients have complication, were 1.10 (Res (HH15)) and 16.4 (Res (LU15)).

CONCLUSION

The resectability indices using 99mTc-GSA liver scintigraphy are useful for the preoperative evaluation of the limitation of hepatic resection.

[Can 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) evaluate the renal function without blood sampling?: consensus report from multicenter study]

A multicenter study was undertaken in Japan to evaluate the correlation between the percentage of renal uptake of 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) estimated by the count-based gamma camera method and the blood clearance of 99mTc-MAG3. Twenty four centers were enrolled and 172 cases were finally analyzed in this study. The renal clearance of 99mTc-MAG3 (TER) was obtained by using a single blood sample taken at 44 min after injection. Comparison of TER and renal uptake provided a coefficient of correlation of 0.874; suggesting that sufficiently accurate quantification of renal function could be obtained from the renal uptake estimate by the gamma camera method. This study also showed that the comparison of renal function might be feasible among patients under the same protocols, although precise and careful consideration is required in each center.

[Arterial infusion chemotherapy with SMAN CS-Lipiodol for hepatocellular carcinoma evaluation of infusion method]

Forty-four patients with hepatocellular carcinoma were treated with oily anticancer agent SMANCS dissolved in Lipiodol (SMANCS-LPD). The local response rate after the first arterial infusion in all patients was 39%, against 63% in 27 patients with Lipiodol accumulation occupying more than two third of tumor areas. Repeated arterial infusion of SMANCS-LPD did not enhance the therapeutic effect. An infusion of 4mg of SMANCS was ineffective for patients with tumors distributing in bilateral lobes of liver, and 6 mg was recommended for such cases.

Precision of the gallbladder ejection fraction obtained with Tc-99m-pyridoxyl-5-methyl-tryptophan (99mTc-PMT) hepatobiliary scintigraphy as compared with the contraction ratio in three-dimensional computed tomography

The gallbladder ejection fraction (GBEF) obtained with Tc-99m-pyridoxyl-5-methyl-tryptophan (99mTc-PMT) hepatobiliary scintigraphy has been used as a parameter of gallbladder function. To determine the accuracy of GBEF, the relationship with the contraction ratio of the gallbladder (GBCR) obtained with three-dimensional helical computed tomography (3D-CT) was studied.

PATIENTS AND METHODS

A normal volunteer, 8 patients suffering from cholecystolithiasis and a patient with gallbladder dyskinesia were examined. The percent initial dose (%ID) for the gallbladder and GBEF with hepatobiliary scintigraphy were used to compare the volume of the gallbladder and GBCR which was measured by 3D-CT.

RESULTS

The %ID of the gallbladder was correlated with the volume of the gallbladder by 3D-CT (Y = 1.000X - 1.818, r = 0.928). GBEF was correlated well with GBCR by 3D-CT (Y = 0.916X + 6.296, r = 0.975).

CONCLUSIONS

The %ID of the gallbladder obtained with hepatobiliary scintigraphy may be a good indicator of the volume of the gallbladder. The accuracy of GBEF was confirmed by comparison with 3D-CT examination. GBEF is considered a useful parameter of pathophysiological gallbladder function.

Combined therapy with external beam irradiation and hepatic arterial epirubicin infusion through an implanted port for advanced hepatocellular carcinoma

Nineteen patients with advanced stage IV hepatocellular carcinoma for which transcatheter arterial embolization and percutaneous ethanol injection were not indicated have been treated by combined therapy with external beam irradiation and repeated hepatic arterial epirubicin infusion through an implanted port. The response rate was 47%, and the median survival was 11.6 months (range, 4.0 to 27.1 months). Eighteen of the 19 patients were able to undergo the infusion therapy on an outpatient basis 3 to 7 weeks after initiation of therapy. This combined therapy was effective in improving tumor-bearing survival and less stressful for the patients because of the minimal therapy-related toxicity and brief hospitalization.

[Proposal on new formulas for renal depth in the technetium-99m-mercaptoacetyltriglycine (MAG3) scintigraphy]

Recently, camera-based techniques to measure effective renal plasma flow (ERPF) have become more popular than single plasma sample techniques because camera-based measurements avoid the necessity of delayed plasma samples and in vitro techniques. The measurements of ERPF are used to estimate the clearance of technetium-99m-mercaptoacetyltriglycine (MAG3). However, camera-based techniques are dependent on an accurate estimate of renal depth to correct for soft-tissue attenuation. Then, new formulas for renal depth correction of technetium-99m-MAG3 clearance in place of Tønnesen's, M. Ito's, K. Itoh's, and Taylor's methods were tried to establish in this paper.

PATIENTS AND METHODS

Eleven hundred and seventy patients without any renal disease were objected. The data from measurement of renal depth using X-ray CT in supine position were analyzed statistically.

RESULTS

The depths of right kidney (Dr) and left kidney (Dl) were 7.33 +/- 1.27 and 7.07 +/- 1.27 cm. The correlation coefficients between Dr and height (H) body weight (W), body surface area (BSA: W0.425 x H0.725 x 0.007184 m2), age, and abdominal thickness (Ta) were 0.275, 0.709, 0.615, 0.087, and 0.743. The correlation coefficients between Dl and H, W, BSA, age, and Ta were 0.269, 0.732, 0.629, 0.029, and 0.812. Ta had best correlation with both Dr and Dl. The calculation formulas for Dr and Dl using Ta were as follows: Dr = 0.32 x Ta + 0.87 cm, and Dl = 0.36 x Ta - 0.08 cm. On the other hand, the multiplex calculation formulas of Dr or Dl with H, W, and Ta were as follows: Dr = 0.18Ta + 8.54 x (W/H) + 0.75 (r = 0.768), and Dl = 0.26Ta + 5.90 x (W/H)-0.16 (r = 0.823).

CONCLUSION

The new regression equations provide superior estimates of renal depth compared to conventional equations. Application of these new formulas into camera-based protocols to determine renal clearances may lead to more accurate measurements of ERPF using technetium-99m-MAG3 scintigraphy.

Compartmental analysis of asialoglycoprotein receptor scintigraphy for quantitative measurement of liver function: a multicentre study

A multicentre study on multicompartmental analysis of hepatic scintigraphy using technetium-99m labelled galactosyl serum albumin (GSA), which binds to the asialoglycoprotein receptor, was carried out at seven institutions in Japan. Seventy-four patients with liver disease received 3 mg (185 MBq) of 99mTc-GSA by intravenous injection. Sequential scanning was performed 30 min after injection to obtain anterior images of the heart and liver, followed by single-photon emission tomography (SPET). The indices included in this analysis were hepatic blood flow (Q) and maximal receptor binding rate (Rmax), which showed a good correlation with semiquantitative ratio indices for 99mTc-GSA, namely the retention rate in blood (HH15) and the hepatic uptake rate (LHL15). Q and Rmax also showed a significant correlation with other measures of hepatic function. When patients were grouped according to the severity of chronic liver damage (hepatocellular functional damage), Q was reduced in the moderate and severe groups, while Rmax was reduced in proportion to the functional stage. Both parameters showed no inter-institution difference using analysis of co-variance with the functional stage as a co-variant. With regard to the hepatic uptake rate, anterior planar images and SPET images gave similar results for Q and Rmax. Acquisition times of 15 or 30 min provided the same results. The multicompartmental model analysis permitted comparable results to be obtained at institutions using different gamma cameras, and is therefore considered a universally applicable method. These results indicate that Q and Rmax are useful general indices for evaluating the functional reserve capacity of the liver.

[Significant findings on CT performed before presence of post-surgical bowel obstruction]

We evaluated whether CT performed before the presence of bowel obstruction (pre-CT) is useful in predicting the presence of post-surgical bowel obstruction. Thirty-three patients with post-surgical bowel obstructions who had pre-CT were reviewed. The pre-CT findings were compared with the findings of CT performed after the presence of bowel obstruction (post-CT) in 16 patients, and with the intraoperative findings in 18 patients. Pre-CT demonstrated many interesting findings, such as a discrepancy in the caliber of the bowel, the presence of two adjacent collapsed loops, a beak-like appearance of the bowel, focal distention and/or wall thickness of bowel loops, and twisted mesentery. Twenty-three (70%) of 33 patients had one or more of these findings on pre-CT. All patients with a surgically proved closed loop obstruction had two adjacent collapsed loops on both pre- and post-CT. In six (86%) of seven patients who had focal dilated bowel loops and twelve (71%) of seventeen patients who had twisted mesentery on pre-CT, conservative management was proved ineffective. Pre-CT showed many significant findings. Attention should be paid to these findings, because they can predict the presence of post-surgical bowel obstruction. In particular, we stress that two adjacent collapsed loops on pre-CT is a sign of the presence of post-surgical closed loop obstruction.

[Examination of scanning technique for lung cancer screening with helical CT]

As a new application of helical CT scanning we evaluated the parameters for lung cancer screening with an extremely low doses and large helical pitch. On the phantom studies, the image quality obtained with the low dose parameter was not inferior to that of the usual screening technique but artifacts were increased with the large helical pitch. A scanning technique using 120 kv, 40-60mA, 10mmth, 20mm/ sec, and a reconstruction pitch of 2 was used for lung cancer screening (screening parameters) (50 cases), and comparison was made between the detectability of the screening parameters and the routine parameters (120 kv, 200mA, 10mmth, 10-13mm/sec, and a reconstruction pitch of 1-1.3). Detectability with the screening parameters was as follows: nodular lesions (< 5mm in size: 76%. 5-10mm: 90-93% 10mm < 100%), linear lesions: 94-95%, infiltrations: 93-100%. There were no false negative lesions, when the reconstruction pitch of the screening parameters was changed from 1 to 0.25. In conclusion, reconstruction pitch had the most influence on lesion detectability.

[Brain CT and MRI findings in fat embolism syndrome]

To elucidate brain CT and MRI findings in fat embolism syndrome (FES), we retrospectively analyzed images from 5 patients with FES during the acute and subacute stages. Brain CT examinations demonstrated brain edema in 2 patients and transient spotty low density lesions in 2 patients. Three patients showed no abnormalities. Brain MRI, however, showed brain abnormalities in all patients during the acute stages. These were revealed as spotty high signal intensity lesions on T2WI, and some showed low intensity on T1WI. These spotty lesions were considered to reflect edematous fluid occurring as a result of the unique pathophysiological condition of FES. While the spotty high signal intensity lesions on T2WI were distributed in the cerebrum, cerebellum, brain stem, thalamus, basal ganglia, internal capsule and corpus callosum, cerebral and cerebellar spotty lesions were characteristically located along the boundary zones of the major vascular territories. This characteristic location might be induced by a hypoxic brain condition in FES because the numerous fat globules present in this condition can block entire brain capillaries. This characteristic signal location on T2WI is a useful indicator for differentiating FES from the primary intra-axial brain injury in patients with multifocal trauma.

[Quantitative analysis of 99mTc-GSA liver scintigraphy with graphical plot method]

99mTc-galactosyl human serum albumin (99mTc-GSA) is a newly developed receptor-binding agent, specific for the asialoglycoprotein receptor, which resides exclusively on the plasma membrane of mammalian hepatocytes. Liver scintigraphy using 99mTc-GSA was performed on 65 patients with liver diseases. Dynamic data were obtained by gamma camera during 20 minutes after the intravenous injection of 3 mg (185 MBq) of 99mTc-GSA. The maximum removal rate of 99mTc-GSA (denoted as P(2)) was measured by two methods: nonlinear five-compartment model analysis adopting the Michaelis-Menten constant for the transfer of 99mTc-GSA from hepatic blood to receptor, and a graphical plot using compartmental dose curves. The graphical plot could estimate easily the maximum removal rate in terms of two data points of 0 and 1 minutes without nonlinear least squares and numerical integration. The results indicated that the maximum removal rate was decided immediately after the intravenous injection of 99mTc-GSA. Although 99mTc-GSA is recognized to accumulate nonlinearly on the liver, the rate constant P(2)*(1/min) of transfer from hepatic blood to the receptor was estimated by graphical plot, assuming a linear five-compartment model. P(2)*Km, which was given by the product of the rate constant P(2)* and the Michaelis constant Km, was well correlated with P(2). Next, for 99mTc-GSA liver scintigraphy, we applied a Patlak plot that was applicable to the linear system, and the rate constant Ku of transfer from extrahepatic blood to the liver was estimated. From the results of graphical plot, it was theoretically shown that Ku represented P(2). This was confirmed by clinical data.

[Fast two-compartment model analysis with 99mTc-GSA liver scintigraphy]

The use of numerical integration method (N. INT) was evaluated in determining parameters by two-compartment model analysis from liver scintigraphy. Among the 15 subjects, 14 had liver cirrhosis or chronic hepatitis, and one was normal. When using N.INT, the sum of two exponential functions on heart regression curve following intravenous injection of 99mTc-galactosyl human serum albumin (99mTc-GSA) was promptly calculated. The parameters obtained from N.INT, including transfer rate of 99mTc-GSA from extrahepatic blood to liver (k1), dissociation rate from liver to extrahepatic blood (k2), and excretion rate from liver to gallblader (k3), were significantly correlated with those obtained by the nonlinear least square method (NLS). k1/k2 was related with the maximum removal rate of 99mTc-GSA obtained from nonlinear five compartment model analysis (r2 = 0.705, n = 15) and also with the severity score of liver disease as classified by the First Department of Surgery, Mie University Medical School (r2 = 0.686, n = 13). In terms of the time required to obtain these parameters, including the blood retention rate of 99mTc-GSA at 15 min after injection (%ID15), N.INT was faster than the traditional method (NLS).

Using Ga-67 scintigraphy in prostatic abscess

The use of Ga-67 scintigraphy (Ga) in prostate inflammatory diseases may be restricted by the difficulty in distinguishing between the accumulation of Ga-67-citrate (Ga-citrate) in the lesion and feces. The diagnosis of prostatic abscess has been mainly made by other radiologic methods without scintigraphic studies and no finding of Ga has been reported. This patient demonstrated that coordinating the findings of Ga-citrate accumulation can be helpful in making a prompt diagnosis of a possibly fatal prostatic abscess, especially in those patients with poorly defined clinical symptoms and high risk factors.

Detection of multiple thromboembolism in congenital antithrombin III deficiency with indium-111-platelet scintigraphy

Congenital deficiency of antithrombin III (AT III), a physiological inhibitor of blood coagulation, may lead to increased thromboembolism. Here, we report a case of multiple thromboembolism associated with congenital AT III deficiency. The diagnosis of systemic thromboembolism was made by 111In-labeled platelet scintigraphy (In-scan) which allowed for the daily assessment of thromboemboli size. Thromboemboli were found not only in sites predicted clinically, but also in unexpected sites. In these patients, thus, a careful whole-body examination is necessary for full detection of thromboemboli. In-scan may be a useful technique for such screening.

[The consideration and performing of pretesting of contrast medium: surveying in Kanagawa]

The pretesting of contrast medium is world widely recognized to be an invaluable method to predict the adverse reactions. It was still required to perform on patients who shall have a contrast examination until recently in Japan. In May of 1990 the contrast drug package insert was reviewed and a statement of "there is no known method to predict the adverse reactions" was included. Although two reports suggested that the percentage of not performing the pretesting was increasing gradually since then, the clinical communications between institutes did not support the truth. This study investigated the problem by surveying the area in Kanagawa-ken neighboring to Tokyo and revealed that: 1. The percentage of non-performing the pretesting is high in radiologist and urologist (both are 40%) but low in other physicians (18%). 2. The risky performances of pretesting in the area without emergent equipment are occurring daily. 3. The percentage of the approval to abandon the pretesting increased significantly (from 46% to 89% with p < 0.01) after the accurate information on pretesting was given. 4. To prevent the tragedy caused by risky performance, actively contacting with and offering the information are necessary.

[CT finding of right diaphragmatic rupture due to blunt trauma--subhepatic hemothorax]

Owing to the poor detectability of the anatomic location of diaphragm on the parallel plane of computed tomography (CT), capability of CT to predict traumatic ruptured diaphragm has been debated in several reports. A specific hematoma (subhepatic hemothorax) adjacent to the posterior attachment of the right diaphragm was identified on CT. The finding originated from herniated liver that migrated to the posterior thoracic wall as a result of gravity, to separate the hemothorax in the supine position. This was surgically proven in two patients after blunt traumatic accident. The finding is useful in predicting right diaphragmatic rupture on CT study. The formation of subhepatic hemothorax, its differential diagnosis and a brief review of diaphragmatic rupture are discussed.

[Effects of intra-arterial infusion chemotherapy with radiation therapy for advanced hepatocellular carcinoma]

Eight cases were treated with periodic arterial infusion therapy from reservoir and four cases with arterial infusion therapy plus 30 Gy's radiation therapy for hepatocellular carcinoma (HCC). The anatomical extent of the tumor was E3 and E4, respectively. We evaluated these forms of therapy from the viewpoint of tumor characteristics, survival time and therapeutic effects. There was no effective case of life prolongation and most of the reservoir only treated cases died a short time after therapy. But no severe complication was observed in reservoir plus radiation cases. One case showed a response, and another case tumor necrosis. The results indicate that this method is effective for advanced HCC.

Evaluation of hepatic transport function by hepatobiliary scintigraphy

The transport kinetics of [99mTc]-pyridoxyl-5-methyltryptophan were studied by three-compartment model analysis for hepatobiliary scintigraphy in 45 patients with chronic viral liver diseases. Three-compartment model analysis was studied using the time-activity curves of the regions of the heart, liver, and biliary tract and intestine (excretory compartment). The k12 (hepatic uptake rate constant), k21 (hepatic efflux rate constant), and ke1 (hepatic excretion rate constant) were calculated by the nonlinear least-squares method. Among the three parameters obtained by model analysis, k12 values more prominently differed among diseases and correlated well with blood tests such as total bilirubin, total bile acids, or 15 min retention of ICG. In conclusion, three-compartment model analysis of the hepatic handling of [99mTc]-pyridoxyl-5-methyltryptophan is useful in evaluating hepatic transport function. k12 is the most sensitive parameter for this.

[Effects of intraarterial infusion chemotherapy on liver function in patients with hepatocellular carcinoma]

Periodic infusion chemotherapy from the reservoir implanted by direct arterial puncture (Seldinger method) was performed in 21 cases of hepatocellular carcinoma. The effectiveness of treatment in terms of efficacy and liver function in about 12 patients who survived more than 6 months was investigated. Owing to the progressive liver atrophy and liver dysfunction with ascites, some cases had to delay infusion treatment. Thus, it is necessary to check liver function regularly.

[Estimation of the reticuloendothelial function by positron emission computed tomography (PET) study in chronic liver disease]

We have developed a new liver scanning agent (Ga-68 human serum albumin microspheres) in a convenient kit for use in positron emission computed tomography (PET). In this study, this scanning agent was evaluated for clinical usefulness as a function test for the reticuloendothelial system. A dose of 5 micrograms/kg (1-2 mCi) of Ga-68 microspheres was injected intravenously to 25 patients, 11 with chronic hepatitis and 14 with liver cirrhosis, and 5 normal volunteers for PET imaging of the liver and spleen using HEADTONE-III (SET 120W). The volumes of the liver and the spleen and the uptakes of Ga-68 microspheres were calculated as an index of the reticuloendothelial system function. In liver cirrhosis the liver volume estimated by PET was decreased and the spleen volume was increased. Both the liver uptake rate and differential absorption ratio (DAR) of the radioactivity were decreased corresponding with the degree of chronic liver disease. The spleen uptake rate was increased with progression of chronic liver diseases, but there was no difference in DAR between normal volunteers and patients with chronic liver disease. it was concluded that PET using Ga-68 microspheres is useful in the evaluation of the function of the reticuloendothelial system.

[Radiotherapy of uterine cervix carcinoma]

Seventy-eight patients with uterine cervix cancer were treated radically with standardized radiation therapy at Teikyo University Hospital in Tokyo from January 1979 to December 1985. The age of these patients ranged from 32 to 88 years old (average age 66.0). The pathology and the stage of them were 71 cases of squamous cell carcinoma (1 in stage I, 11 in stage II, 58 in stage III and 1 in stage IV) and 7 cases of adenocarcinoma (6 in stage III and 1 in stage IV). The cumulative survival rates for 5 years by Kaplan-Meier method were 71.5% for squamous cell carcinoma stage II, 47.4% for squamous cell carcinoma stage III and 0% for adenocarcinoma stage III. Radiation injury was studied by the grading system of Kottmeier-NIRS in Japan. The incidence of the injuries for grade 2 and 3 was 12.8% (10/78), and the items of those were rectal injury 5.1% (4/78) and sigmoidal colonic injury 7.7% (6/78). The results of survival rate were fair for the squamous cell carcinoma compared with the other reports but poor for adenocarcinoma stage III. Concerning the therapy for advanced adenocarcinoma of the uterine cervix, special consideration should be given for irradiation doses or infusion chemotherapy.

The relationship between a subcutaneously placed afferent jejunal loop in a hepaticojejunostomy and postoperative cholangitis

A subcutaneously placed afferent jejunl loop pexis, which is often performed during a hepaticojejunostomy, opens a route to the biliary tract, through which appropriate instruments can be passed should postoperative complications arise, requiring a choledochoscopy, the removal of calculi, and for the dilatation of the anastomotic site. From our clinical experience with such a pexis, however, postoperative cholangitis showing a transient fever with abdominal pain and liver dysfunction frequently develops. Further, in cases in which a subsequent dissection of this jejunal pexis was performed, there was a reduction in the incidence of cholangitis, which suggests a possible correlationship between such a pexis and cholangitis. In this investigation, bile stasis in jejunal loop has been studied, using hepatobiliary scintiscanning in examining 31 patients given a hepaticojejunostomy. Fourteen of these patients were also given a jejunal loop pexis, and 17 patients were without such a pexis. Bile stasis was found to be more frequent in the group given a jejunal loop pexis (p less than 0.001). Further, bile stasis was found in 90% of patients showing postoperative cholangitis whereas postoperative cholangitis was observed in 60% of patients with bile stasis (p less than 0.01). Thus, based on the data obtained, as well as our clinical experience, it would seem that a subcutaneously placed jejunal loop pexis should be avoided while performing a hepaticojejunostomy, unless the possibility of anastomotic stenosis and/or the retention of stones are strongly expected.

[Improved contrast enhancement with a positive pressure drip infusion method and 350 mg I/ml high concentration contrast media in routine contrast enhanced CT]

Sixty cases of routine contrast enhanced CT were analyzed about the utilities of positive pressure drip infusion method using high concentration contrast media 350 mgI/ml, 100 ml. They were divided into three groups and each twenty cases were received positive pressure drip infusion method using Iohexol 350 mg/ml, 100 ml (350PP), positive pressure drip infusion method using Iohexol 300 mgI/ml, 100 ml (300PP) or conventional drip infusion method using Iohexol 300 mgI/ml, 100 ml (300DI). Enhancement effects of the liver parenchyma, the aorta and the spleen at upper, middle and lower levels of the liver were evaluated with increased attenuation on pre- and postcontrast CT. And intrahepatic contrast was evaluated with attenuation difference between liver parenchyma and intrahepatic vessels on postcontrast CT. In result, 300PP kept better enhancement effects and obtained better intrahepatic contrast than 300DI at the each level of the liver, and 350PP was still better than 300PP. The analysis of relationship between intrahepatic contrast and body weight suggested that 300PP was the optimal choice for the cases with 40-50 kg body weight and 350PP was for the ones with 50-60 kg as the infusion method of routine contrast enhanced CT. And the dose of contrast media seemed to be more needed for the cases over 60 kg body weight. 350PP and 300PP were concluded as useful, safe and simple methods for routine contrast enhanced CT of the liver.

Diagnostic evaluation of hepatobiliary scintigraphy using 99mTc-N-pyridoxyl-5-methyltryptophan in acute cholecystitis

Hepatobiliary scintigraphy using 99mTc-N-pyridoxyl-5-methyl-tryptophan (99mTc-PMT) was carried out in 80 patients with benign biliary diseases, excluding cholecystectomized patients, for the diagnosis of acute cholecystitis. Using the conventional diagnostic criteria based on nonvisualization of the gallbladder in acute cholecystitis, the specificity, efficiency and positive predictability test results were 63%, 72% and 45%, respectively. When delayed intestinal transit of radioactive material was added to this criteria, the diagnostic value was significantly improved (p less than 0.01); the specificity, efficiency and positive predictability test results were 97%, 97% and 90%, respectively. Delayed intestinal transit of radioactive material should be considered in the diagnosis of acute cholecystitis.

An experimental study of deep-vein thrombosis using 99mTc-fibrinogen

The in vivo and in vitro behavior of 99mTc-fibrinogen was investigated in rats, as well as the relationship between its incorporation into thrombi and gamma imaging in deep-vein thrombosis. 99mTc-Fibrinogen manifested satisfactory physicochemical and biological properties, and its in vivo stability was demonstrated by a high ability to clot in the circulating blood. High ratios of thrombus-to-blood were found between 4 and 24 h after the injection of this agent in 30-min thrombi. Among 30-min to 7-day thrombi, the highest ratio was found in 1-day thrombi and the lowest in 7-day thrombi. Hot spots on the scan were clearly visualized in fresh thrombi. It is concluded that 99mTc-fibrinogen is a very useful and promising scanning agent for the diagnosis of active thrombosis.