Detection of osteomyelitis at fracture nonunion sites: comparison of two scintigraphic methods

Forty-nine patients with 50 fracture nonunions 4-48 months after injury underwent technetium-99m methylene diphosphonate (99mTc-MDP) scintigraphy on day 1, combined 99mTc-MDP and indium-111 leukocyte (111In-WBC) scintigraphy on day 2, and gallium-67 (67Ga) scintigraphy on day 3. The results were compared to evaluate the relative abilities of these scintigraphic techniques to detect osteomyelitis. Nine patients had clinical evidence of infection at the time of imaging, and 40 patients (41 fractures) did not. Open-biopsy cultures were performed at all fracture sites and were positive at 21 (42%) of the 50 sites. Combined 99mTc-MDP/111In-WBC images were interpreted with the use of two criteria. A positive study by the first criterion required 111In-WBC localization in the region of the nonunion fracture. A positive study by the second criterion required 111In-WBC localization in bone at the fracture site. The first criterion yielded a sensitivity of 84%, specificity of 72%, and accuracy of 74%; the specificity improved to 97% with an accuracy of 88% when the second criterion was used. Ten (25%) of the 40 patients thought not to have osteomyelitis by clinical criteria at the time of imaging had true-positive 99mTc-MDP/111In-WBC studies by biopsy culture results. Gallium-67 studies were interpreted as nondiagnostic if localization of radioisotope at fracture sites was equal to that with 99mTc-MDP, positive if 67Ga localization was greater than that of 99mTc-MDP, and negative if it was less than that of 99mTc-MDP. Twenty-one 67Ga studies were interpreted as nondiagnostic; 11 (52%) of the 21 had culture-positive fracture sites. The accuracy of 67Ga/99mTc-MDP imaging was 39%. Combined 99mTc-MDP/111In-WBC imaging is useful in the detection of osteomyelitis at fracture nonunion sites and improves the specificity of 111In-WBC imaging by differentiating inflammation/infection in adjacent soft tissue from osteomyelitis at the fracture site. Gallium-67 with 99mTc-MDP imaging is not sufficiently reliable in this clinical setting to be useful as an indicator for osteomyelitis.     

Scintigraphy with 99mTc-HMPAO labeled leukocytes in acute cholecystitis

99mTc-HMPAO labeled leukocyte scanning was performed on 38 patients with clinically suspected acute cholecystitis (AC) to evaluate its diagnostic value. The typical finding was an increasing accumulation of the tracer in the gallbladder wall in a 4 hour series of scintigrams. Leukocyte scan was positive in 16 of 17 patients with surgically and histologically confirmed AC. There were no false-positive findings. The sensitivity, specificity, and accuracy of scintigraphy were 94, 100, and 96%, respectively. In 2 patients with acute acalculous cholecystitis true-positive findings were observed. Scintigraphy with 99mTc-HMPAO labeled leukocytes is a valuable new imaging method in AC.     

Indium-111-leukocyte/technetium-99m-MDP bone and magnetic resonance imaging: difficulty of diagnosing osteomyelitis in patients with neuropathic osteoarthropathy

Fourteen patients (16 sites) with clinical and/or radiographic evidence of neuropathic osteoarthropathy (Charcot joints) were evaluated with combined indium-111-leukocyte (111In-WBC) and technetium-99m-methylene diphosphonate (99mTc-MDP) bone imaging for suspected osteomyelitis. Magnetic resonance (MR) images were obtained in seven patients. Using a positive bone culture as the criterion for the presence of osteomyelitis, there were four true-positive studies, six true-negative sites, and one false-negative 111In-WBC study. Five of 16 sites (31%) had false-positive 111In-WBC uptake at noninfected sites. There were four true-positive and three false-positive MR studies. All false-positives showed at least moderately abnormal findings by both techniques at sites of rapidly progressing osteoarthropathy of recent onset. In this preliminary study, both techniques appear to be sensitive for detection of osteomyelitis, and a negative study makes osteomyelitis unlikely. However, the findings of 111In-WBC/99mTc-MDP and MR images at sites of rapidly progressing, noninfected neuropathic osteoarthropathy may be indistinguishable from those of osteomyelitis.     

The role of technetium-99m iminodiacetic acid (IDA) cholescintigraphy in acute acalculous cholecystitis

Technetium-99m iminodiacetic acid (IDA) cholescintigraphy was performed in 15 patients with acute acalculous cholecystitis. Fourteen of the 15 patients with acute disease had positive findings, indicating the presence of cystic duct or common duct obstruction. One case in which the gallbladder was visualized failed to respond to sincalide stimulation; this was classified as a suggestive finding of disease. The diagnostic accuracy of 99mTc-IDA cholescintigraphy was far superior to the other imaging studies used (8 sonograms, 1 intravenous cholangiogram, 3 oral cholecystograms, 1 percutaneous transhepatic cholangiogram). The 99mTc-IDA study is recommended as the imaging procedure of choice for examining patients with suspected acute acalculous cholecystitis.     

Association between false negative hepatobiliary scans and initial gallbladder visualization after 30 min

We have reviewed the experience of our institution and the literature concerning the use of hepatobiliary scintigraphy for the diagnosis of acute cholecystitis. The aim of this study was to assess whether the hepatobiliary scintigraphic finding of initial gallbladder visualization within 30 min is a more reliable criterion for excluding acute cholecystitis than gallbladder visualization within 1 h after tracer injection. In our institution's consecutive series, 113 of 211 hepatobiliary studies had gallbladder visualization within 1 h. Gallbladder visualization time in this group had a log normal distribution, with gallbladder visualization occurring within 30 min in 107 of 113 (95%). Gallbladder visualization occurred between 31 and 60 min in only 6 (5%); nevertheless, our one false negative study came from this small subgroup of patient studies (P = 0.05). Review of the literature (1645 patients with iminodiacetic acid [99mTc-IDA] derivative studies) revealed 6 further timed false negative results with gallbladder visualization within 1 h. Of these studies, in 4 (67%) the gallbladder was visualized between 31 and 60 min and in only 2 before 30 min. One of these latter 2 patients had a rare anatomy. Analysis of the pooled institutional and literature data gave an estimated false negative rate of 21% if the gallbladder was visualized between 31 and 60 min. This was significantly higher (P less than 0.001) than the 0.5% false negative rate when the gallbladder was seen prior to 30 min, but similar to the false negative rate of 16% reported by Weissmann et al. for studies with initial visualization after 1 h.(ABSTRACT TRUNCATED AT 250 WORDS)     

Enterogastric reflux in suspected acute cholecystitis

Ninety patients undergoing Tc-99m disofenin hepatobiliary scintigraphy for suspected acute cholecystitis were assessed for enterogastric reflux. Seventy-seven cases showed bowel activity by one hour and were included in the study. Twenty-six percent (20/77) showed definite enterogastric reflux. The gastric activity tended to clear rapidly, even though patients remained supine during examination. Six of 20 patients (30%) with enterogastric reflux had gallbladder visualization. Of these six, one had acute cholecystitis and one had resolving acute cholecystitis with gallstone pancreatitis. There was one case each of pancreatitis, amebic abscess, sepsis, and one normal. Thus, of 20 patients with enterogastric reflux, 16 had acute cholecystitis (80%). Twenty-three of seventy-seven patients (30%) had surgically proven acute cholecystitis: of these, 16 of 23 (70% sensitivity) had gastric reflux, and 50 of 54 without acute cholecystitis did not have reflux (93% specificity). The overall accuracy of enterogastric reflux for acute cholecystitis is 86%. Gastric reflux seen on cholescintigraphy is a secondary sign of acute cholecystitis. Reflux may be related to duodenal irritation from the adjacent inflamed gallbladder.     

99Tcm-nanocolloid imaging in inflammatory bowel disease

We have used 99Tcm-labelled nanocolloid in an attempt to locate areas of inflamed bowel wall or abscesses in five patients with ulcerative colitis and nine with Crohn's disease. The scintigraphic findings were evaluated by comparison with those of recent barium studies and, in three patients, with surgical findings at laparotomy. It proved difficult to localize segments of inflamed bowel accurately with 99Tcm-nanocolloid because of the accumulation of radioactivity in the gut lumen, especially 2 or more hours after injection. However, there was little uptake of the labelled nanocolloid by areas of inflamed gut wall in the period before 2 h. When 99Tcm-nanocolloid scans were compared with 111In-WBC scans in eight patients who had both investigations, 99Tcm-nanocolloid scintigraphy was considerably less sensitive than 111In-WBC scintigraphy. One abscess was located correctly; the other was obscured by nearby bladder and bone marrow radioactivity. We conclude that 99Tcm-nanocolloid scanning is neither sensitive nor reliable enough for assessing the location of inflamed bowel wall or the presence of abscess in patients with inflammatory bowel disease.     

Comparison of Indium-111-labeled leukocyte scintigraphy and Technetium-99m joint scintigraphy in rheumatoid arthritis and osteoarthritis

This study was undertaken to evaluate the use of Indium-111-labeled leukocyte (111In-WBC) imaging compared with Technetium-99m pertechnetate (99mTcO4-) imaging in 19 patients with rheumatoid arthritis (RA) and 8 with osteoarthritis. Knee and wrist joints were evaluated for both radionuclides. The results indicated a good correlation of the clinical assessment of pain and swelling with joint uptake ratio (JUR) between 111In-WBC and 99mTcO4- in RA and osteoarthritis patients. We observed a discrepancy in both imagings in "burned out" cases. It was concluded that a JUR of 111In-WBC could distinguish active RA from inactive RA or osteoarthritis at a value of 1.15 and that the use of 111In-WBC was a more reliable procedure than 99mTcO4-.     

Morphine-augmented cholescintigraphy: its efficacy in detecting acute cholecystitis

Cholescintigrams were performed in 158 patients suspected of having acute cholecystitis after administration of 185 Mbq (5 mCi) of 99mTc-mebrofenin or disofenin. Morphine sulfate, 0.04 mg/kg was given intravenously if there was nonvisualization of the gallbladder at 40-60 min provided that radiotracer was seen within the small bowel. Acute cholecystitis was deemed present if there was nonvisualization of the gallbladder 30 min post-morphine administration; no cystic duct obstruction was present if the gallbladder was demonstrated pre- or post-morphine administration. A final diagnosis was estimated in 51 postoperative patients histologically, the remainder having their final diagnosis gleaned from their medical records. The sensitivity, specificity, positive and negative predictive value of morphine-augmented cholescintigraphy in detecting acute cholecystitis was 94.6, 99.1, 97.2, and 98.3%, respectively. These findings indicate that morphine-augmented cholescintigraphy detects acute cholecystitis with as high a degree of accuracy as conventional hepatobiliary scintigraphy, yet requires only 1.5 hr to establish the diagnosis.     

Detection of subacute infectious foci with indium-111-labeled autologous leukocytes and indium-111-labeled human nonspecific immunoglobulin G: a prospective comparative study

In 35 patients suspected of an infectious focus, the outcome of scintigraphy with 111In-labeled autologous leukocytes (WBC) and 111In-labeled human nonspecific immunoglobulin G (IgG) was evaluated in a prospective comparative study. Clinical, roentgenologic and microbiologic findings were considered to be proof of the presence of infection or inflammation. In this group of patients with mainly subacute infections, 111In-IgG scintigraphy performed significantly better than 111In-WBC scintigraphy, especially in infections of the locomotor system, but also in various soft-tissue infections. Both techniques showed disappointing results in patients with disseminated yersinia infection and in some patients with tuberculosis. Overall sensitivity and specificity was 74% and 100% for 111In-IgG scintigraphy and 52% and 78% for 111In-WBC scintigraphy, respectively.     

Computed tomography in acute cholecystitis

It has been our experience that acute cholecystitis can frequently be diagnosed on the basis of computed tomography (CT) alone, without the need for further confirmatory studies. This capability has not been emphasized in the radiologic or surgical literature.Retrospective review of CT scans performed in patients with the initial diagnosis of acute abdomen or sepsis due to abdominal source yielded 29 patients in whom a retrospective CT diagnosis of acute cholecystitis was made when all three of the following findings were present: gallbladder wall thickening (>3 mm), gallbladder distention, and pericholecystic abnormality (either fluid or abnormal fat).Pathologic or surgical follow-up was available in 22 of 29 patients. In 20 of 22 (91%) patients who underwent surgery, there was a pathologic or surgical diagnosis of acute cholecystitis. There were two falsepositive diagnoses: one patient with chronic cholecystitis and one patient with adenocarcinoma of the neck of the gallbladder.A confident diagnosis of acute cholecystitis can be made on CT scan in the appropriate clinical setting when all three of these criteria are met: gallbladder distention, gallbladder wall thickening, and pericholecystic abnormality. If one of these criteria is not met or is equivocal, biliary scintigraphy or ultrasonography may be needed to confirm the diagnosis.     

Personal experience in 71 consecutive patients with acute cholecystitis

PURPOSE: Acute cholecystitis is one of the most frequent abdominal inflammatory processes. If untreated or misdiagnosed it can result in severe complications such as gallbladder rupture, abscesses, or peritonitis. We retrospectively reviewed a series of 71 consecutive patients with surgical confirmation of acute cholecystitis and now compare the results of the diagnostic techniques we used preoperatively. MATERIAL AND METHODS: Over 16 months, 71 consecutive patients (42 women and 29 men; age range: 34-84 years, mean: 58) with acute abdominal pain were operated on for acute cholecystitis at Cardarelli Hospital, Naples. Abdominal plain film was performed in 65 of 71 cases, abdominal US in 69 and abdominal CT in 6. On abdominal plain films, we retrospectively searched the following signs: densities projected over the gallbladder, linear calcifications in gallbladder walls, gallbladder enlargement, focal gas collections within the gallbladder, and air-fluid levels in the gallbladder lumen. On US images we looked for: gallbladder wall thickening (> 3 mm), intraluminal content in the gallbladder, pericholecystic fluid, US Murphy's sign, and gallbladder distension. On CT images, we investigated: gallbladder distension, wall thickening, intraluminal content, pericholecystic fluid, and inflammatory changes in pericholecystic fat. Associated complications of cholecystitis were also searched on all images. RESULTS: On plain abdominal films we found densities projected over the gallbladder (16.9%) and linear calcifications in the gallbladder wall (4.6%). Abdominal US demonstrated gallbladder wall thickening (56.5%), one or more gallstone(s) (85.5%), pericholecystic fluid (14.5%), gallbladder distension (46.4%), and US Murphy's sign (39.1%). Abdominal CT showed gallbladder wall thickening (83.3%), gallbladder distension (66.6%), pericholecystic fluid (66.6%), gallstones (50%), inflammatory changes in pericholecystic fat (33.3%), and increased bile density (> 20 HU) (33.3%). CONCLUSIONS: US appears to be the most useful imaging technique in patients with suspected acute cholecystitis, for both screening and final diagnosis. CT plays a limited role in the early assessment of these patients, but can be a useful tool in diagnosing acute cholecystitis in patients with questionable physical findings or in investigating related complications.     

A diagnostic dilemma of atypical gallbladder appearance on Tc-99m HIDA cholescintigraphy resolved with SPECT/CT

Tc-99m HIDA cholescintigraphy is the diagnostic procedure of choice for acute cholecystitis. Acute cholecystitis is associated in vast majority of the cases with cystic duct obstruction. The demonstration of presence (cystic duct patency) or absence (cystic duct obstruction) of visualization of the gallbladder on cholescintigraphy is critical to the diagnosis of acute cholecystitis. The visualization of the gallbladder rules out acute cholecystitis in most of the cases. Although, in most cases, determination of visualization or nonvisualization of gallbladder is straight forward, occasionally it can be challenging. We describe a patient with suspected acute cholecystitis, in whom an unusual appearance of the gallbladder on hepatobiliary scintigraphy was clarified with SPECT/CT, an approach that is rarely used in Tc-99m HIDA cholescintigraphy.     

Distinguishing benign from malignant gallbladder wall thickening using FDG-PET

OBJECTIVE: Because thickening of the gallbladder wall is observed not only in patients with gallbladder cancer but also in those with benign diseases such as chronic cholecystitis and gallbladder adenomyosis, it is difficult to distinguish between benign and malignant gallbladder wall thickening by conventional techniques of diagnostic imaging such as computed tomography (CT), magnetic resonance imaging (MRI), and abdominal ultrasonography (US). In the present study, we attempted to distinguish between benign and malignant gallbladder wall thickening by means of fluorine-18-fluorodeoxyglucose (FDG)-Positron emission tomography (PET). METHODS: FDG-PET was performed in 12 patients with gallbladder wall thickening detected by CT or US, to determine whether it was benign or malignant. Emission scans were taken, beginning 45 minutes after intravenous administration of FDG, and SUV was calculated as an indicator of glucose metabolism. RESULTS: Of the 12 patients, 4 showed positive uptake of FDG in the gallbladder wall. Of these 4 patients, 3 had gallbladder cancer. The remaining one, who had chronic cholecystitis, had false-positive findings. The other 8 patients had negative uptake of FDG in the gallbladder wall. Two of these 8 underwent surgical resection, which yielded a diagnosis of chronic cholecystitis. The other 6 patients exhibited no sign of gallbladder malignancy and have been followed without active treatment. CONCLUSIONS: FDG-PET appears able to distinguish between benign and malignant gallbladder wall thickening.     

PIPIDA scintigraphy for cholecystitis: false positives in alcoholism and total parenteral nutrition

A review of gallbladder scintigraphy in patients with potentially compromised hepatobiliary function revealed two groups in whom cholecystitis might be mistakenly diagnosed. In 200 consecutive hospitalized patients studied with technetium-99m-PIPIDA for acute cholecystitis or cholestasis, there were 41 alcoholics and 17 patients on total parenteral nutrition. In 60% of the alcoholics and 92% of those on parenteral nutrition, absent or delayed visualization of the gallbladder occurred without physical or clinical evidence of cholecystitis. A cholecystagogue, sincalide, did not prevent the false-positive features which presumably are due to altered bile flow kinetics related to alcoholism and parenteral nutrition. Four patients on parenteral nutrition undergoing cholecystectomy for suspected cholecystitis had normal gallbladders filled with jellylike viscous thick bile. A positive (nonvisualized or delayed visualized) gallbladder PIPIDA scintigram in these two populations should not be interpreted as indicating a need for cholecystectomy.     

Acute cholecystitis: MR findings and differentiation from chronic cholecystitis

PURPOSE: To retrospectively determine the sensitivity and specificity of magnetic resonance (MR) imaging for differentiation between acute and chronic cholecystitis, with histopathologic analysis as the reference standard. MATERIALS AND METHODS: Institutional review board approval with waived informed consent was obtained for this HIPAA-compliant study. Four reviewers blinded to the cholecystitis type but aware that cholecystitis was present retrospectively evaluated MR images for predetermined findings in 32 patients (15 male, 17 female; mean age +/- standard deviation, 55 years +/- 20) with histopathologically proved acute or chronic cholecystitis. The final MR diagnoses and MR findings in both groups were compared with each other and with the histopathologic diagnoses to determine the sensitivity and specificity of MR imaging. Chi(2) tests were used to detect differences in MR findings between the acute and chronic cholecystitis groups. RESULTS: MR imaging sensitivity and specificity for detection of acute cholecystitis were 95% (18 of 19 patients) and 69% (nine of 13 patients), respectively. The sensitivities of increased gallbladder wall enhancement and increased transient pericholecystic hepatic enhancement were 74% (14 of 19 patients) and 62% (10 of 16 patients), respectively. Both findings had 92% (12 of 13 patients) specificity. Sensitivities of increased wall thickness, pericholecystic fluid, and adjacent fat signal intensity changes were 100% (19 of 19 patients), 95% (18 of 19 patients), and 95% (18 of 19 patients), respectively; specificities were 54% (seven of 13 patients), 38% (five of 13 patients), and 54% (seven of 13 patients), respectively. Pericholecystic abscess, intraluminal membranes, and wall irregularity or defect each had 100% (13 of 13 patients) specificity; sensitivities were 11% (two of 19 patients), 26% (five of 19 patients), and 21% (four of 19 patients), respectively. Increased gallbladder wall enhancement (P<.001) and increased transient pericholecystic hepatic enhancement (P=.003) were the most significantly different between acute and chronic cholecystitis. CONCLUSION: Increased gallbladder wall enhancement and increased transient pericholecystic hepatic enhancement had the highest combination of sensitivity and specificity for the diagnosis and differentiation of acute and chronic cholecystitis.     

Diagnosis of acute cholecystitis by cholescintigraphy: significance of pericholecystic hepatic uptake

Uptake of radionuclide by the liver next to the gallbladder in cholescintigraphy has been described as a useful secondary sign with a high positive predictive value for the diagnosis of acute cholecystitis. We retrospectively examined 780 consecutive cholescintigrams to (1) determine the positive predictive value at 1 hr of this sign for acute cholecystitis and (2) ascertain if the presence or absence of this finding could differentiate acute from gangrenous cholecystitis. Pericholecystic hepatic activity was present at 1 hr in 48 (34%) of 141 scans in which the gallbladder was not visualized, and cholecystectomy was performed within 6 days of scintigraphy. Forty-five of these patients had acute and three had chronic cholecystitis (94% positive predictive value for acute cholecystitis). In addition, 57% of patients with gangrenous cholecystitis exhibited pericholecystic hepatic activity, and the frequency of this finding was significantly higher (p less than .006) in gangrenous than in acute cholecystitis. In summary, pericholecystic hepatic uptake is a valuable secondary sign in the cholescintigraphic diagnosis of acute cholecystitis. The significance of the finding is (1) a high positive predictive value for acute disease at 1 hr and (2) a statistically significant increased frequency in patients with gangrenous cholecystitis.     

Scintigraphic gallbladder visualization with gangrenous acalculous cholecystitis

Hepatobiliary scintigraphy evaluates the biliary clearance of Tc-99m-labeled iminodiacetic acid agents (Tc-99m IDA) and has a high sensitivity and specificity for the diagnosis of acute cholecystitis. False-negative studies are extremely rare. We describe an apparently normal nonmorphine-augmented hepatobiliary study in gangrenous acalculous cholecystitis. Based on clinical findings, computed tomography, and ultrasound demonstration of a dilated gallbladder, a cholecystectomy was performed. Pathologic examination of the gallbladder revealed acute gangrenous cholecystitis with culture positive for Klebsiella pneumoniae.     

Pericholecystic hepatic activity in cholescintigraphy

Gallbladder nonvisualization in cholescintigraphy has been shown to be a reliable finding in acute cholecystitis. In some cholescintigrams, we have observed faintly increased pericholecystic hepatic activity in conjunction with gallbladder nonvisualization. To determine the frequency and significance of the pericholecystic hepatic activity finding, we evaluated 334 consecutive adult patients who had cholescintigrams with technetium-99m diisopropylphenylcarboamoyl iminodiacetic acid. Pericholecystic hepatic activity was seen in 21% of the abnormal scans demonstrating gallbladder nonvisualization but in none of the other scans. Thirteen of these patients underwent surgery; 11 (85%) were found to have acute cholecystitis, and two (15%) had chronic cholecystitis. Four patients (31%) had acute gangrenous cholecystitis, and five (39%) had cholecystitis complicated by gallbladder perforation. The pericholecystic hepatic activity sign is not specific for gangrenous cholecystitis or gallbladder perforation but does reliably indicate inflammatory gallbladder disease and is associated with a relatively high incidence of cholecystitis complicated by perforation.     

Ultrasonography of adrenal masses: usual features

99mTc-HIDA is concentrated by the hepatocytes and excreted into the biliary system; the gallbladder, common bile duct, and early accumulation in the duodenum are visualized within 30 minutes of intravenous administration. The authors studied the utility of 99mTc-HIDA imaging in both acute and chronic cholecystitis and hepatobiliary disease in the presence of jaundice: (a) all normal gallbladders exhibited filling, (b) absence of visualization indicated gallbladder disease and/or cystic duct obstruction, (c) visualization of the gallbladder after cholecystokinin-induced emptying excluded an obstructed cystic duct and acute cholecystitis, and (d) a definitive diagnosis of hepatocellular disease, partial and complete obstruction, is possible in jaundiced patients with hyperbilirubinemias up to 5 mg%. Beyond that level, 99mT-HIDA imaging was of qualified value. The technique is useful in assessing biliary drainage in jaundiced patients with surgically altered biliary tract anatomy.