Positron emission tomography scanning in the evaluation of hepatocellular carcinoma.

BACKGROUND/AIMS: 18F-fluorodeoxyglucose uptake allows estimation of glucose metabolism by tumor cells using positron emission tomography (PET). We evaluated the role of PET imaging in the diagnosis of hepatocellular carcinoma. METHODS: PET images were collected after intravenous injection of 8-12 mCi of 18F-FDG in 20 patients with hepatocellular carcinoma (HCC). PET tumor activity level was assessed on a scale of 1 to 4 compared to normal liver tissue. The PET score was compared with abdominal computerized tomography (CT) scan results and between tumors of different grades and differentiation. RESULTS: Of the 20 patients studied, 11 (55%) had positive PET scans (PET score: 3 or 4) while nine (45%) were negative (PET score: 1 or 2). CT scan was positive in 18 patients (90%) and negative in two (10%). PET, however, revealed metastases in three patients that were not seen on CT. On pathological review, well-differentiated and low-grade tumors had lower PET scores. Comparison of the well-differentiated with the moderately- and poorly-differentiated tumors revealed a statistically significant difference. No statistical significance was observed between the moderately- and poorly-differentiated tumors or between different tumor grades and PET scores. CONCLUSIONS: The sensitivity of PET in diagnosis of HCC was 55% compared to 90% for CT scanning, although only PET detected some tumors (including distant metastases). Well-differentiated and low tumor grades had lower activity on PET and correspondingly lower PET scores. PET imaging may help assess tumor differentiation and may be useful in the diagnosis and staging and prognostication of HCC as an adjunct to CT.

Sonographic diagnosis of unsuspected gallbladder cancer: imaging findings in comparison with benign gallbladder conditions.

OBJECTIVE: Several sonographic findings were analyzed to determine their significance in distinguishing gallbladder cancer from benign conditions of the gallbladder. The analyzed findings were gallstone number and size; floating stones; displaced stones; wall thickening, irregularity, and echogenicity; mucosal plaque; intraluminal mass; gallbladder-replacing mass; invasive gallbladder mass; gallbladder mucosal discontinuity; hyperechoic gallbladder mucosa; and submucosal or transmural echolucency. MATERIALS AND METHODS: Sonograms of 20 patients with unsuspected, pathologically proven gallbaldder cancer and 65 patients with benign gallbladder conditions (predominantly acute or chronic cholecystitis) were retrospectively assessed by two observers who were unaware of experimental conditions. Gallstone number and size were assessed, and the presence of floating stone (neither settling nor wall-adherent), displaced stone (lifted from the gallbladder wall by mass or focal wall thickening), wall irregularity, mucosal plaque, intracystic mass, and gallbladder-replacing or invasive mass was evaluated. The echogenicity pattern of the gallbladder wall was characterized, and its thickness was measured and classified as normal/mildly thickened (< 7 mm) or moderately/severely thickened (> or = 7 mm). In addition, the gallbladder wall was evaluated for discontinuous mucosal echo, hyperechoic mucosa, submucosal or mural echolucency, and pericholecystic fluid collection. Sonographic findings were compared by the Mann-Whitney test for nonparametric variables and by Student's t test for continuous variables. RESULTS: Solitary gallstone, displaced stone, intraluminal mass, gallbladder-replacing or invasive mass, and discontinuity of the mucosal echo were all statistically significantly more common in patients with gallbladder cancer (.001 < p < .05). Mucosal plaque and wall irregularity were nonspecific findings. Gallbladder wall thickening by itself was nonspecific, although associated echolayering, transmural or submucosal edema, or a distinctly specular mucosal lining favored benign etiologies. CONCLUSION: Several sonographic findings were significantly more common in patients with gallbladder cancer compared with patients with benign gallbladder conditions. Assessment of these signs may be helpful in distinguishing gallbladder cancer from benign conditions of the gallbladder.

Assessment of renal allograft pathology by scintigraphic and ultrasound index-markers.

The efficacies of two scintigraphic and two sonographic techniques and resultant index values, as markers of renal allograft pathology, were assessed. Index values of 183 combined scintigraphic and sonographic examinations in 47 graft recipients were compared to the pathological diagnosis of transplant biopsies and subsequent clinical outcome. All recipients were studied with baseline imaging techniques postoperatively, again when indicated by predefined clinical criteria, and prior to graft biopsy. The scintigraphic technique involved the calculation of indices of thrombotic activity and cortical graft perfusion. Ultrasound involved determination of the Doppler resistance index of Pourcelot and estimations of graft volume from real time images. A decreased cortical perfusion index was, overall, the most sensitive index of acute or chronic graft pathology, but it lacked specificity. Increased thrombotic and resistance indices were 96% and 86% sensitive for acute vascular rejection and were 82% and 76% specific. Jointly increased thrombotic and resistance indices improved the specificity for acute vascular rejection to 98%. An increase in graft volume of more than 50% over stable values was 100% sensitive and 92% specific for acute interstitial rejection, and 95% specific when paired with a normal thrombotic index. A marked increase in the thrombotic index was 100% sensitive for cyclosporine-induced thrombotic microangiopathy, but only 49% specific. The specificity of a markedly increased thrombotic index for thrombotic microangiopathy improved to 93% when the Doppler resistance index remained normal or was only marginally elevated. None of the scintigraphic or ultrasound indices were helpful for the diagnosis of acute tubular necrosis, chronic rejection, recurrent glomerulopathy, or graft infection.

Pancreatic lymphangioma: CT, MRI, and angiographic features.

An unusual case of pancreatic lymphangioma presenting as a large mid-abdominal mass with sunburst pattern of calcification is herein described. The findings noted on computed tomography (CT), magnetic resonance imaging (MRI), and mesenteric angiography are illustrated.

Endometrial hyperplasia: value of endometrial thickness in ultrasonographic diagnosis and clinical significance.

The records of 90 patients with histologically proven endometrial hyperplasia (EH) were reviewed retrospectively. Eleven of these patients had pelvic ultrasound examinations available. These were compared to the pelvic ultrasound examinations of 19 patients with a histologically normal endometrium, available in 126 consecutive patients seen over the same period of time. Patients with EH had a mean endometrial thickness of 18.8 mm (range 8 mm to 45 mm) vs 5.4 mm (range 2 mm to 10 mm) in the control group. This difference in thickness was statistically significant (p much less than .01). The specificity and sensitivity of endometrial thickness in the diagnosis of EH were 100% and 81%, respectively, when 10 mm was taken as the upper limit of normal. Ultrasonographically demonstrable endometrial characteristics can differentiate EH from normal endometrium in a great majority of cases. The clinicopathological significance of EH is discussed.

Pancreatic transplant rejection: assessment with duplex US.

The value of duplex ultrasonography (US) in the assessment of pancreatic transplants was studied in 22 patients over a 1 1/2-year period. Ninety-eight duplex US examinations were performed, and the Doppler arterial resistive indexes (RIs) correlated with clinical events after transplantation. The RI was 0.70 or less in the parenchymal vessels in all instances of normal transplant function and greater than 0.70 in seven of eight clinical episodes of rejection (87.5%). In all studies performed during these eight cases of rejection, the positive predictive value of an RI exceeding 0.70 was 100%. The negative predictive value of an RI of less than 0.70 in excluding rejection was 90%. High RI values were not found in isolated episodes of cyclosporine toxicity, pancreatitis, peripancreatic hemorrhage, or infection. Duplex US may prove to be more accurate in the diagnosis of rejection of pancreatic transplants versus renal transplants because the former cases have fewer causes of increased vascular impedance and diminished perfusion.

Perforation of the retroperitoneal sigmoid colon secondary to fracture-dislocation of the left sacroiliac joint: case report.

Most traumatic injuries of the sigmoid colon are penetrating, such as those due to stab and bullet wounds, but an occasional patient may have a perforated colon as a result of a pelvic fracture. Such lesions may be occult, resulting in delayed diagnosis, with substantial morbidity. Injury to the sigmoid colon in association with sacroiliac fracture has apparently not been described in the English-language literature. This paper reports such a case and describes the mechanism of injury and its recognition.

Role of sonography in trichobezoars.

Three cases of trichobezoar (12/F, 5/F, and 35/M) are reported. All patients presented with an epigastric mass and the diagnosis was not suspected clinically. They were referred for sonography which revealed a hyperechoic curvilinear dense strip at the anterior margin of the lesion associated with marked acoustic shadowing and no through transmission. Similar findings were noted in all three cases. In vitro ultrasound scans performed on the operated specimen in one case confirmed that the sonographic findings were the result of the trichobezoar mass. Diagnosis was confirmed in all the cases by barium meal and surgery.

Body computed tomography findings in systemic lupus erythematosus.

Fifty-five computed tomography scans in 27 patients with systemic lupus erythematosus were reviewed. The most frequent indication for scanning was suspected intraabdominal sepsis, and the most frequent finding was mild lymphadenopathy. Renal abnormalities were: subcapsular hematoma, focal defects, overall enlargement, and diminution of size. Other findings included serositis, bowel wall thickening with pneumatosis intestinalis, pancreatic pseudocyst, and hepatic and splenic enlargement. Five abscesses were found that were indistinguishable from other fluid collections. Computed tomography was helpful in clinical evaluation and in some cases changed management.

Treatment of frostbite with i.v. streptokinase: an experimental study in rabbits.

Experiments were conducted in 32 rabbits to determine whether treatment with IV streptokinase can effectively limit the extent of tissue damage associated with frostbite injury of the hind limbs. Other variables studied were the temperature of the tissue during freezing, the time taken to rewarm the exposed limbs, and the delay between the initiation of treatment with streptokinase and cessation of freezing. A control group of 16 rabbits was not given streptokinase. The extent of tissue damage was estimated by sequential radionuclide perfusion scans of the exposed limbs. This estimate was based on the proportional loss of tissue perfusion on subsequent twice-weekly nuclear scans in comparison with that shown by scans performed immediately after thawing. Pathologic changes in exposed tissues were studied by histology. Streptokinase treatment and rapid rewarming both resulted in less tissue damage at all freezing temperatures. Streptokinase was most beneficial when given 12 hr after freezing, but was effective even when treatment was delayed up to 48 hr.

Frostbite: experimental assessment of tissue damage using Tc-99m pyrophosphate. Work in progress.

We designed an experimental model using a new method of freezing to study the pathogenesis and treatment of frostbite. Frostbite was simulated in a manner that closely resembles that which occurs in a natural environment. We used a radionuclide imaging technique to monitor the evolution and extent of tissue damage relative to temperature, rate of freezing, and controlled rewarming. Characteristic sequential changes were demonstrated on sequential nuclear scans. Nonperfusion, followed by perfusion, and finally again by nonperfusion occurred in all areas in which necrosis developed. The reappearance of nonperfusion corresponded to vascular injury and thrombosis evidenced at pathologic examination. We determined that lack of tissue perfusion corresponded to tissue injury. We believe that our experimental model provides an effective means of evaluating potential therapeutic regimens.

Magnetic resonance imaging in planning limb-salvage surgery for primary malignant tumors of bone.

In defining the linear extent of a malignant tumor in a long bone, radiographs, computerized tomography, and scintigraphy are routinely employed, especially when non-ablative surgery is being considered. The drawbacks of these modalities in defining the true intracompartmental extent of disease within a bone can largely be overcome with the use of magnetic resonance imaging. We did a prospective analysis of magnetic resonance imaging in sixteen consecutive patients with a primary malignant tumor of a long bone, and it showed that this modality has clinical promise of being more precise than the other modalities in defining the true proximal and distal extent of a tumor in a long bone. Coronal images permit easier planning of surgical techniques for salvage of a limb using an allograft than do a multiplicity of transverse images.

Magnetic resonance imaging of lesions of synovial origin.

Three patients with histologically differing lesions of synovial origin and two with synovial cysts, one of which was a dissecting popliteal cyst, were examined by magnetic resonance imaging (MR) and computerized tomography (CT). The three histologically proven synovial lesions were synovial sarcoma, diffuse giant cell tumor of tendon sheath, and synovial chondromatosis. In two of the five patients MR provided better anatomic and morphologic appreciation than CT, while in the others they were of equal value. CT demonstrated calcification in two of the lesions while on MR calcification could be identified in only one patient where it outlined the mass. MR did not demonstrate calcification in the substance of the diffuse giant cell tumor of tendon sheath. Coronal, transverse, and sagittal images of magnetic resonance graphically demonstrated the extent of the soft tissue masses and their relationship to bone, vessels, and soft tissue structures. Synovial sarcoma had a shorter T1 than diffuse giant cell tumor of tendon sheath (these two lesions being of comparable size) and also had a uniformly longer T2. The dissecting popliteal cyst showed the most intense signals on the T1 weighted images, while the uncomplicated synovial cyst showed a long T1. On the T2 weighted images, each type of cyst showed a long T2. The variance and overlap of intensity of MR signals suggest limited specificity in predicting the histologic nature of the synovial lesion.

Intravenous DSA and duplex sonography as screening examinations for carotid disease: comparison in 102 vessels.

Duplex sonography and intravenous digital subtraction angiography (DSA) were compared in 102 carotid bifurcations in 51 patients. Sonograms were adequate in 87 (85%) vessels and angiograms were adequate on at least one view in 86 (84%) vessels. An adequate image was obtained by one or the other method in all but two vessels (98%). Although most vessels were seen well on one view only on DSA, agreement with sonography was exact in 73% of compared vessels and acceptable in 96%. Furthermore, no difference was found in the rate of agreement with sonography for vessels seen well by DSA on two or more views compared with those seen well on one view only. It was concluded that DSA and sonography are comparable screening methods for carotid disease and that a suboptimal study by either can usually be compensated for by performance of the other.

Ipsilateral decubitus position for percutaneous CT-guided adrenal biopsy.

Positioning the patient on the side to be biopsied elevates and relatively immobilizes the diaphragmatic leaf on the dependent side, allowing percutaneous adrenal needle biopsy by a direct posterior approach without traversing lung tissue. The ipsilateral decubitus position was used successfully for biopsy of four small adrenal lesions in which lung precluded a direct posterior approach in the prone position. In addition, the relative stability of the diaphragmatic leaf further facilitated accurate needle placement.

CT characteristics of aortic atherosclerotic aneurysm versus aortic dissection.

In an attempt to better define criteria for the diagnosis of atherosclerotic aneurysm (AA) and aortic dissection (AD) using CT the scans of 60 documented aortic lesions were reviewed. Hyperdensity of the aortic wall at multiple levels was found to be specific for AD. Central displacement of atheromatous calcification and deformity of the residual aortic lumen were more common in AD than in AA. Peripheral location of aortic wall calcification and a round aortic lumen in cross section were more common in AA than in AD. Central calcification in AA appeared to be associated with a serious short-term prognosis in several cases. A thickened aortic wall of low density was more common in AA than in acute AD, but this relationship was not significant when acute and chronic ADs were considered as a single group. Wall thickness correlated with cross-sectional size of the aortic lesion in AA but not in AD. The mean maximum wall thickness exceeded 1 cm for both AA and AD and was not significantly different between the two; contrary statements have been made in the angiographic literature.

CT findings in leukemia.

Review of 84 computed tomographic (CT) scans in leukemic patients demonstrated a wide spectrum of abnormalities. Findings caused by leukemia were lymphadenopathy, visceral enlargement, focal defects, and tissue infiltration. Hemorrhage was by far the most common complication and could usually be characterized on the noncontrast CT scan. The distinction between old hematomas, foci of infection, and leukemic infiltration could not be made with certainty without CT-guided aspiration. Unusual instances of sepsis, such as microabscesses of the liver and typhlitis, were seen.

Percutaneous recanalization of iliac artery occlusions: an alternative to surgery in the high-risk patient.

Percutaneous transluminal angioplasty was performed successfully in three patients with total occlusions involving the iliac artery. Two patients had occlusion of the external iliac artery and the third patient had occlusion of the common iliac artery. The vessels were still patent at 3-12 months after the procedure. One complication occurred involving a thrombus in the common femoral artery of the diseased leg. The thrombus was surgically removed under local anesthesia. In high-risk patients, percutaneous transluminal angioplasty of total iliac artery occlusions may represent a viable alternative to surgery.

CT of bilateral adrenal hemorrhage with acute adrenal insufficiency in the adult.

Bilateral adrenal hemorrhage and acute adrenal insufficiency in three acutely ill patients occurred as a complication of pneumonia in two and recent abdominal surgery in the third. The diagnosis was unsuspected in each case before abdominal computed tomography (CT), which showed bilateral adrenal masses. CT was done for suspected intraabdominal sepsis. Adrenal insufficiency was confirmed by endocrine studies, and each patient promptly recovered with steroid replacement therapy. Follow-up CT showed diminution or disappearance of the masses and density changes consistent with resolving hematomas.

Ultrasonic tissue characterization of atheromatous plaques using a high resolution real time scanner.

Atheromatous plaques obtained at autopsies and surgical carotid endarterectomy specimens were scanned in a water bath with an 8 MHz high resolution real time instrument. The findings were correlated with histology at corresponding sites in each specimen. Fatty streaks were not detectable by ultrasound. Small fibro fatty plaques appeared as localized thickening of the arterial wall with little change in echogenicity or echo texture. In larger fibro fatty lesions, sizable aggregates of amorphous lipid residue appeared less echogenic than adjacent tissues and regions of dense fibrosis more echogenic. Densely calcified foci in plaques were highly echogenic and associated with acoustic shadowing. Surface irregularities of plaque at ultrasound may simulate ulceration. Ulcers, evident at gross inspection, appeared as marked surface irregularities or excavations at ultrasound. The basis of the findings and their relevance to clinical vascular ultrasound imaging are discussed.