Computerized liver imaging: relationship with quantitatively estimated histological parameters in liver cirrhosis

In liver cirrhosis, increased splenic uptake of radiocolloid, causing the liver-to-spleen (L/S) ratio to decrease, is a characteristic finding, especially during advanced illness. Histologically, advanced liver cirrhosis shows progressive replacement of hepatic parenchyma by fibrous tracts, making it possible to quantify both image and histological parameters. On this basis, the authors performed this study in 39 alcoholic cirrhotic patients in order to determine the relationship between the L/S ratio and right-to-left hepatic lobe ratio (RL/LL) and the degree of fibrosis, fat droplet area, total fat amount, and hepatocyte area. The authors tested if it is possible to predict the degree of fibrosis on the basis of image features or on a combination of image and biochemical parameters, using multiple correlation studies. The degree of fibrosis correlates with the L/S ratio (r = -0.48). The degree of correlation improved using prothrombin, gamma globulin and L/S ratio (r = 0.656), but not enough to allow an accurate estimation of the degree of fibrosis on the basis of a combination of imaging and biochemical data. Neither RL/LL nor L/S ratios significantly correlated with fatty infiltration, fat droplet area, or hepatocyte enlargement. Thus, liver imaging is not useful in quantifying the main histological changes observed in alcoholic liver cirrhosis.     

Reversibility of pulmonary telangiectasia in liver cirrhosis evidenced by serial dynamic pulmonary perfusion imaging

Pulmonary perfusion imaging with Tc-99m MAA revealed significant uptake in the lungs, brain, spleen, and both kidneys of a 48-year-old woman with liver cirrhosis and pulmonary telangiectasia associated with marked hypoxemia and cyanosis. Dynamic pulmonary perfusion imaging revealed a gradual reduction after peak uptake in both lungs. Several weeks after albumin replacement, the hypoxia and dyspnea disappeared with no change in hepatocellular function. At that time, dynamic pulmonary perfusion imaging revealed a plateau-like time-activity curve of uptake in the lungs, as compared with the findings obtained during the state of severe hypoxemia. These observations suggest that pulmonary telangiectasia in a patient with liver cirrhosis may be due to functional vasodilatation. Serial dynamic pulmonary perfusion imaging indicates the passage of the MAA particles through the widened lumen of the pulmonary alveolar capillaries.     

Overestimation of splenic size and underestimation of hepatic size by radiocolloid scintigraphy in advanced cirrhosis of the liver: an autopsy correlation

The radiocolloid liver-spleen scintigrams of seven patients with advanced cirrhosis of the liver were correlated with autopsy results. The data showed scintigraphic overestimation of splenic size and underestimation of hepatic size. The causes of underestimation of the liver size were: rotation of the liver due to ascites; photon attenuation by ascitic fluid; and/or decreased and in homogeneous distribution of radiocolloid in the diseased liver. The splenic size/weight was overestimated because of lack of the effects of ascites and the usually marked increase in splenic radioactivity. Awareness of the underestimation of the liver weight/size and overestimation of the splenic weight/size occurring on the radiocolloid liver-spleen scan of patient with advanced alcoholic cirrhosis of the liver may help avoid misinterpretation.     

Internal medicine diagnosis of splenic diseases

In an adult man the spleen serves two physiologic functions. It is an organ of the immune system, the second function is the sequestration and removal of normal and abnormal blood cells. Most diseases of spleen are associated with enlargement of the organ. Causes of splenomegaly are liver diseases with portal hypertension, infections, malignant leukemias or lymphomas often combined with lymph node enlargement, collagen vascular diseases or Felty's syndrome, chronic hemolytic syndromes and infiltrative diseases such as Gaucher's disease. Some diseases associated with splenic enlargement respond to splenectomy.     

Radiocolloid liver imaging in hepatic steatosis

In a review of 60 patients with fatty infiltration of the liver documented by Xe-133 imaging, 43% had normal radiocolloid liver images, and 57% had abnormal images with various combinations of hepatomegaly, mottling, splenomegaly, and splenic shift of radioactivity. None, however, showed focal defects. Fatty infiltrates do not simulate mass lesions on the radiocolloid study of the liver, and an area of photon deficiency in the presence of hepatic steatosis points to an additional pathologic process. The interpretation of the radiocolloid liver image is unhindered by fatty infiltration when searching for discrete space-occupying lesions.     

Detection of pulmonary telangiectasia using dynamic pulmonary perfusion imaging in patients with liver cirrhosis

Two cases of liver cirrhosis associated with marked hypoxemia are presented. Chest radiographs and cardiopulmonary function showed no abnormalities, except for the low diffusion capacity of carbon monoxide and slight elevation of the shunt ratio (20 and 6.2%, respectively), as estimated under conditions of 100% oxygen inhalation. Pulmonary perfusion imaging with Tc-99m macroaggregated albumin (MAA) revealed a significant radioisotope uptake in the lungs, brain, spleen, and both kidneys. Shunt ratios, estimated by the quantitative radionuclide method, were 60 and 68%, respectively. Dynamic pulmonary perfusion imaging revealed a gradual reduction in uptake in all areas of both lungs. The discrepancy of the shunt ratio between the two methods results from an abnormal dilatation of alveolar capillaries. The gradual reduction of radioactivity in areas of the lungs is caused by the passage of MAA particles through widened pulmonary capillaries.     

Diagnosis of cirrhosis and hepatitis by quantitative hepatic and other reticuloendothelial clearance rates.

Although methods for measuring colloid clearance rates have been described, they are not commonly used. Rather, most clinicians rely on the relative radiocolloid accummulation in the liver and spleen as estimated by visual inspection of liver scans. This method lacks objectivity, however, and only indirectly reflects the rate of radiocolloid clearance. We have developed a noninvasive kinetic technique for measuring radiocolloid clearance by the liver, spleen, and other reticuloendothelial tissues. The clerance-rate constants obtained by this technique appear to differentiate among cirrhosis, fatty metamorphosis, hepatitis, and normal function. In normal subjects, the mean clearance-rate constants for the liver, spleen, and extrahepatosplenic reticuloendothelial system were 16.0, 1.4, and 3.4 ml/min per 100 ml of plasma, respectively. The mean hepatic clearance-rate constant was normal in hepatitis (16.8 ml/min per 100 ml), reduced in cirrhosis (5.7), and slightly reduced in fatty metamorphosis (10.4). Both the hepatic-to-splenic and the hepatic-to-extrahepatosplenic ratios of clearance-rate constants were reduced in cirrhosis and slightly reduced in fatty metamorphosis and hepatitis. Interestingly, the splenic clearance-rate constants were normal in these three diseases.     

Demonstrating alcoholic cirrhosis of the liver by Tc-99m BIDA scintigram

Six patients with decompensated cirrhosis of the liver underwent Tc-99m BIDA studies. All demonstrated 1) persistently high blood pool activity in the heart, lung, and soft tissue, 2) slow hepatic tracer uptake, 3) prolonged liver-to-bowel transit time, and 4) visualization of an enlarged spleen. Four of the six patients demonstrated evidence of ascites and in one patient there were visible collateral veins of the abdomen. These findings are due primarily to hepatic dysfunction and retaining Tc-99m BIDA in blood pool because of Tc-99m BIDA exclusively hepatic excretion and little or no alternative renal excretion. All six Tc-99m sulfur colloid studies were performed concomitantly. Except for bone marrow uptake and reversal of the normal liver-spleen ratio of radioactivity, the imaging abnormalities observed with Tc-99m BIDA were similar to those seen by Tc-99m SC. It is concluded that with Tc-99m BIDA studies, three of six abnormal findings, as described, suggest a decompensated stage of cirrhosis of the liver.     

Unusual splenic image in massive bleeding after capsular tear

A woman, who had suffered blunt trauma to the thorax and abdomen, had radiocolloid splenic images which revealed splenomegaly, a shift of radiocolloid to the spleen, and a minor interruption of splenic continuity along the medial border. At laparotomy, it was estimated that 2.51 of blood had been lost via a splenic laceration. It was hypothesized that, when the capsule was ruptured (without a major intrasplenic component), a clot failed to form. This led to massive bleeding, and possible venous or other vasoactive phenomena which may have accounted for the splenomegaly and shift of radiocolloid.     

Ferumoxides and Tc-99m sulfur colloid: Comparison of the tumor-to-liver uptake in focal nodular hyperplasia

The tumor-to-liver uptake of two reticuloendothelial agents, namely ferumoxides and technetium-99m (Tc-99m) sulfur colloid, was compared in focal nodular hyperplasia (FNH). Twelve patients with FNH who had undergone ferumoxides-enhanced MR imaging and planar Tc-99m sulfur colloid scintigraphy within 1 year were included from the study. Fourteen patients with FNH with a diameter larger than 3 cm were selected for the comparison. The tumor-to-liver ferumoxides uptake was calculated and the Tc-99m sulfur colloid uptake was assessed visually. Ferumoxides uptake was observed in all but one patient with FNH (mean tumor-to-liver ratio = .36). The six tumors showing normal (n = 5) or increased (n = 1) radiocolloid uptake when compared to the liver accumulated more ferumoxides than the eight tumors showing decreased radiocolloid uptake (P < .01). However, in some tumors, no direct relation was observed between ferumoxides and Tc-99m sulfur colloid uptake. Our observations suggest that ferumoxides uptake might not exactly mimic Tc-99m sulfur colloid uptake in FNH.     

Computed tomography features of nonalcoholic steatohepatitis with histopathologic correlation

OBJECTIVE: This study was conducted to describe the computed tomography (CT) features of nonalcoholic steatohepatitis (NASH) and to evaluate if the CT features could be used to diagnose and stage NASH. METHODS: From 1994 until 2004, pathology records revealed 68 patients with NASH. Of these, 12 patients underwent CT scans before (n=6), on the same day as (n=3), or after (n=3) a liver biopsy. Using the same database, 9 patients with steatosis alone evaluated with a CT scan before (n=2), on the same day as (n=3), or after (n=4) the liver biopsy were selected as a control group. Two radiologists measured liver attenuation (compared with spleen) and assessed the pattern of steatosis, craniocaudal liver span, caudate-to-right lobe ratio, preportal space distance, and presence of porta hepatis lymph nodes and ascites. Biopsy specimens were assessed by a pathologist, and the degree of necroinflammatory activity, steatosis, and fibrosis was determined. Histopathologic and CT findings were compared between patients with NASH and patients with steatosis alone using the Mann-Whitney U test and Fisher exact test. RESULTS: In patients with NASH, the mean liver-to-spleen attenuation ratio was 0.66 (range: 0.1-1.1). Steatosis was diffuse (n=9), geographic or nonlobar (n=2), or diffuse with an area of focal sparing (n=1). The liver craniocaudal span varied from 17.5 to 25.5 cm (mean=21.4 cm), and hepatomegaly was present in 11 (91.7%) patients. The caudate-to-right-lobe ratio (mean=0.43) and preportal space (mean=4.5 mm) were normal in all cases. Porta hepatis lymph nodes were present in 7 (58.3%) patients; their mean dimensions were 16 mmx11 mm. Ascites was absent in all patients. On histopathology, the degree of necroinflammatory activity was mild (n=9), moderate (n=1), or severe (n=2). The degree of steatosis was 33% to 66% (n=5) or >67% (n=7). All but 3 patients had fibrosis; 6 had focal nonbridging fibrosis, 1 had multifocal nonbridging fibrosis, and 2 had bridging fibrosis. There was a significant correlation between the degree of steatosis on pathologic examination and the liver-to-spleen attenuation ratio on CT (P=0.048). The severity of inflammation and stage of fibrosis on pathologic examination did not correlate with the CT features. Among patients with steatosis alone, the mean liver-to-spleen attenuation ratio was 0.80 (range: 0.3-1.2); the craniocaudal liver span varied from 12 to 20 cm (mean=16 cm); hepatomegaly was present in 2 (22.2%) patients; the caudate-to-right lobe ratio was normal in all patients, with a mean of 0.36 (range: 0.22-0.47); the preportal space distance was enlarged in 2 cases (mean=7.5 mm, range: 1-16 mm); porta hepatis lymph nodes were present in 7 (77.8%) patients, and their mean dimensions were 11 mmx8 mm (large axis range: 6-19 mm, short axis range: 4-14 mm); and no patient had ascites. There was a significant difference in the craniocaudal liver span between patients with NASH (mean=21 cm) and patients with steatosis (mean=16 cm) (P<0.05). The caudate-to-right-lobe ratio was also significantly different between patients with NASH (mean=0.43) and patients with steatosis (mean=0.36) (P<0.05). There were no significant differences in liver-to-spleen attenuation ratios, measurements of preportal space, or the presence of porta hepatic lymph nodes. CONCLUSION: The CT features of NASH include steatosis, hepatomegaly, and porta hepatis lymph nodes, and the liver-to-spleen attenuation ratio correlated with the degree of steatosis on histopathology. Patients with NASH had a greater liver span and increased caudate-to-right-lobe-ratio compared with patients with steatosis alone.     

Ectopic splenomegaly in Felty's syndrome

A 50-year-old woman with Felty's syndrome, who presented with "menopausal" symptoms, was found to have a large pelvic mass on physical exam. Computed tomography of the pelvis led to an incorrect diagnosis of malignancy, while radionuclide imaging using Tc-99m sulfur colloid confirmed the diagnosis of ectopic splenomegaly.     

Role of the chest radiograph in the preoperative assessment of the pulmonary function in patients with cirrhosis candidates to liver transplant

PURPOSE: To appraise the role of chest radiography (CXR) in the clinical assessment of pulmonary complications occurring as a result of liver disease of any cause, a standardised reading of CXR was compared both with the results of lung function studies and with the severity of liver disease in 60 consecutive patients with cirrhosis candidates to liver transplant. MATERIALS AND METHODS: CXR were scored for signs of cardiomegaly, enlargement of central and or peripheral vessels, hyperkinetic circulatory and/or intravascular volume states, abnormally increased interstitial lung markings, and pleural effusion by three independent observers. RESULTS: The CXR score of this complete vascular-interstitial deficiency showed a high interobserver reproducibility and was significantly increased in those patients with a more decompensated liver cirrhosis. Moreover, a larger number of CXR signs of vascular and interstitial deficiency was present in those patients who had a more severe cirrhosis (Child-Pugh class 3). Functional indices of pulmonary gas exchange and diffusing capacity were worse in patients with end-stage liver cirrhosis, and for some indices the correlation was statistically significant. The comparison between lung function and CXR score showed that on average lung function impairment was significantly less severe in patients with lower CXR scores. CONCLUSIONS: In conclusion, the information derived from a standardised reading of CXR is valuable in the clinical assessment of the pulmonary damage induced by liver cirrhosis as it allows discrimination of classes of severity of liver disease and of lung function impairment. When integrated with physiologic measurements and, if necessary, with high resolution tomographic studies, chest radiography helps to discriminate patients with advanced liver cirrhosis and progressing towards a hepatopulmonary syndrome, who need a proper therapeutic management.     

Bone marrow extension and pelvic bone marrow activity in alcoholic liver disease. A RES scintigraphic investigation.

Red bone marrow extension and increased central bone marrow activity were found in 21 patients with alcoholic liver disease investigated with scintigraphy of the reticuloendothelial system. The patients had no concurrent disease known to alter red bone marrow distribution. The bone marrow extension and the increased pelvic bone marrow activity may be explained as being secondary to a decreased radiocolloid uptake in the liver and could thus be a sign of decreased reticuloendothelial capacity.     

Diagnosis of chronic liver disease from liver scintiscans by artificial neural networks

Artificial neural networks were used in the diagnosis of chronic liver disease based on liver scintiscanning. One hundred and thirty-seven patients with chronic liver disease (12 with chronic persistent hepatitis, 39 with chronic aggressive hepatitis, and 86 with cirrhosis) and 25 healthy controls were studied. Sixty-five subjects (10 healthy controls, 20 patients with chronic hepatitis, and 35 patients with cirrhosis of the liver) were used in the establishment of a neural network. Liver scintiscans were taken starting 20 min after the intravenous injection of 111 MBq of Tc-99m-phytate. The neural network was used to evaluate five items judged from information on liver scintiscans: the ratio of the sizes of the left and right lobes, splenomegaly, radioactivity in the bone marrow, deformity of the liver and distribution of radioactivity in the liver. The neural network was designed to distinguish between three liver conditions (healthy liver, chronic hepatitis and cirrhosis) on the basis of these five items. The diagnostic accuracy with the neural network was 86% for patients with chronic hepatitis and 93% for patients with cirrhosis. With conventional scoring, the accuracy was 77% for patients with chronic hepatitis and 87% for patients with cirrhosis. Our findings suggest that artificial neural networks may be useful for the diagnosis of chronic liver diseases from liver scintiscans.     

Hypoxemia and liver cirrhosis (hepatopulmonary syndrome) in eight patients: comparison of the central and peripheral pulmonary vasculature

PURPOSE: To evaluate the pulmonary vasculature in patients with hepatopulmonary syndrome. MATERIALS AND METHODS: Conventional computed tomographic (CT) scans in eight patients with hepatopulmonary syndrome were retrospectively evaluated to compare the diameters of the pulmonary trunk, right and left main pulmonary arteries, and peripheral pulmonary vasculature in the right posterior basal segment with those in eight healthy subjects and in four patients with normoxemic cirrhosis. With thin-section CT, the ratio of segmental arterial diameter to adjacent bronchial diameter in the right lower lobe in four patients with hepatopulmonary syndrome was compared with that in four patients with normoxemic cirrhosis. RESULTS: In patients with hepatopulmonary syndrome, the peripheral pulmonary vasculature was significantly dilated compared with that in control subjects and in patients with normoxemic cirrhosis (P = .002); however, the central pulmonary arteries were not significantly dilated (P > .05). At thin-section CT, the ratio of segmental arterial diameter to adjacent bronchial diameter was significantly greater than that in patients with normoxemic cirrhosis (P < .05). CONCLUSION: In patients with hepatopulmonary syndrome, the peripheral pulmonary vasculature is significantly dilated. Dilatation of the peripheral pulmonary vasculature may be helpful in the diagnosis of hepatopulmonary syndrome.     

Radiocolloid scans in evaluating splenic response to external radiation.

By use of 99mTc-sulfur colloid, splenic size as well as liver/spleen ratio of ratioactivity was determined after external radiation of the abdomen. In six patients receiving about 2,000 R whole-abdominal radiation, there was no atrophy of the spleen or abnormal distribution in the liver/spleen ratio of radioactivity (that is, the spleen was still functional). Serial studies in a 7-year-old boy with acute lymphoblastic leukemia in remission showed that 1,450 R splenic radiation did not result in any appreciable change in the length of the organ. In a woman with lymphosarcoma, a change in spleen size did not occur until a dose of 1,800 R was delivered. Another patient had apparently normal uptake of radiocolloid 5 years after 3,600 R. Hence the normal spleen and the spleen affected by other diseases may be far more resistant to external radiation than the spleen diseased with chronic myelocytic leukemia. Spleen scans can be useful in documenting the response of the organ to radiation.     

Diseases of the hepatopulmonary axis.

Hepatopulmonary syndrome is the most widely recognized of the processes associated with end-stage liver disease. Chronic liver dysfunction is associated with pulmonary manifestations due to alterations in the production or clearance of circulating cytokines and other mediators. Hepatopulmonary syndrome results in hypoxemia due to pulmonary vasodilatation with significant arteriovenous shunting and ventilation-perfusion mismatch. Hepatic hydrothorax may develop in patients with cirrhosis and ascites. Rarely, pulmonary hypertension occurs in the setting of portal hypertension. A second group of disorders may primarily affect the lungs and liver (the hepatopulmonary axis). Among these are the congenital conditions alpha(1)-antitrypsin deficiency and cystic fibrosis. Autoimmune liver disease may be associated with lymphocytic interstitial pneumonitis, fibrosing alveolitis, intrapulmonary granulomas, and bronchiolitis obliterans with organizing pneumonia. Sarcoidosis affects the lung and liver in up to 70% of patients. Medications such as amiodarone can result in a characteristic radiologic appearance of pulmonary and hepatic toxic effects. Knowledge of these associations will assist the radiologist in forming a meaningful differential diagnosis and may influence treatment decisions.     

Reflections on the etiology of hot spots on liver scans

Liver scintigraphy demonstrated areas of increased radiocolloid uptake in three cases with obstruction of the superior vena cava and extensive collateral circulation through the veins of the thoracic wall. The pattern of the hyperactive zones is indicative of predominant vascularization of the liver via the umbilical vein, with high colloid particle deposition in the quadrate lobe and adjacent part of the right lobe. These liver regions vascularized by the first intrahepatic branches of the umbilical vein as demonstrated by postmortem angiography, probably extract a great portion of the tracer dose, resulting in localized hyperactivity. An identical liver scan image was, however, found in a fourth case without evident superior vena cava syndrome. In this patient, presenting with a bronchus carcinoma with paratracheal metastatic lymph nodes, there is no explanation (collateral circulation without vena caval obstruction?) for the abnormal tracer distribution within the liver.     

Diagnosis of diffuse hepatocellular diseases using SPECT

In the scintigraphic diagnosis of diffuse hepatocellular diseases, increased splenic uptake of colloids and splenomegaly are helpful signs. To quantify these patterns, the volume and activity of liver and spleen were measured by using single photon emission computed tomography (SPECT). The spleen-to-liver (S/L) ratios in volume and activity that were calculated from SPECT images were estimated in normal individuals and in patients with diffuse hepatocellular diseases. The maximum normal limits of S/L ratios of volume, activity, and activity/volume were predicted as 0.19, 0.087, and 0.72 (mean +/- 2 s.d.). Twenty-two of twenty-three patients (96%) with liver cirrhosis had at least two elevated S/L ratios, and three elevated S/L ratios could clearly differentiate the patient with liver cirrhosis from normal individuals. On the other hand, only six patients (32%) with chronic hepatitis had elevation of any S/L ratio. Abnormal S/L ratios of activity/volume in the range from 0.72 to 1.05 were not obvious on planar or SPECT images.