Joint scintigraphy using technetium-99m pyrophosphate in experimental hemarthrosis.

To determine the validity of a method for induction of experimental hemarthrosis in dogs and for the nuclear imaging of hemarthrosis, serial technetium-99m pyrophosphate [( 99mTc]PYP) flow and blood-pool scans were performed monthly in eight dogs who received bi-weekly injections of autologous blood into their femoro-tibial joints (also called stifle joint). In four control dogs, one joint was injected with saline while the other joint received only a sham injection. In addition, two dogs received intra-articular injections of autologous blood into their right stifle joint and saline into their left stifle joint. These dogs were studied with 99mTcO4 joint scintigraphy at monthly intervals. The dogs were periodically taken out of the study and explored surgically. Pathologic examination of synovial tissue was performed. Serial radiographs were also obtained and correlated with the scan and surgical findings. There was a striking abnormal increase in blood-pool activity of [99mTc]PYP in the treated stifle joints, commencing at the first examination after 1 mo of blood injections and continuing for the length of the study. All radiographs showed only minimal joint space widening and some soft-tissue swelling. On pathologic examination, both grossly and microscopically, there was profuse pannus formation, with intense inflammatory infiltrate replacing much of the subsynovial fat. The scintigraphic findings correlated well with these pathologic findings. This study not only validates this method for simulating hemophilic hemarthrosis but also suggests that [99mTc]PYP joint scintigraphy is a simple, and noninvasive method for monitoring the early changes in hemophilic arthropathy and is superior to pertechnetate imaging for this disease process. Instead of the previously recommended delayed bone images, we recommend, in addition, flow studies to assess joint hypervascularity and immediate static images to visualize the synovium and joint capsule.

Upper airway distensibility and collapsibility in patients with obstructive sleep apnea.

The present study was performed to evaluate the distensibility and collapsibility characteristics of regional segments of the UA in patients with OSA and in normal subjects in response to changes in airway pressure. Seventeen male patients with moderately severe OSA and 13 normal subjects underwent CT of the UA in the supine position while awake. Axial views were obtained from the level of the hard palate to the hypopharynx under conditions of -5, 0, and +10 cm H2O of CAP. The results indicated that the Amin occurred within 20 mm of the hard palate in the retropalatal region of the UA in 16 (94 percent) of the 17 patients and in 12 (92 percent) of the 13 normal subjects. Continuous negative airway pressure of -5 cm H2O failed to significantly decrease either Amin or Amean in either the patients or normal subjects, suggesting good UA load compensation during wakefulness. Continuous positive airway pressure of 10 cm H2O significantly increased Amin and Amean to a similar extent in both groups. The Amin was significantly smaller by 40 percent, 33 percent, and 37 percent in the patients with OSA, compared to the normal subjects, at -5, 0, and +10 cm H2O of CAP, respectively. In contrast, Amean did not differ between the groups. The CT scan criterion of Amin less than or greater than 1.0 cm2 during tidal ventilation of atmospheric pressure correctly categorized patients with OSA and normal subjects with an accuracy of 70 percent. While the behavior of the UA in response to nasal CPAP and CNAP failed to increase the accuracy of CT scan criteria to a level sufficient for clinical use in the diagnosis of OSA, the results clearly indicate that structural changes in the UA contribute to the development of OSA.

Detection of right-to-left shunt with radionuclide angiocardiography in refractory hypoxemia.

A significant right-to-left shunt at the atrial level was diagnosed by radionuclide angiocardiographic examination in a patient with hypoxemia whose perfusion scan showed no pulmonary uptake. The shunt occurred through a patent foramen ovale due to increased right ventricular afterload, subsequently confirmed at autopsy. It is concluded that radionuclide angiocardiography with technetium 99m macroaggregated albumin (99mTc MAA), followed immediately by a perfusion lung scan, may have a place in the evaluation of patients with refractory hypoxemia, since pulmonary embolism and/or right-to-left shunting are two of several causes of hypoxemia in the absence of congenital heart disease. A review of the literature on different pathophysiologic factors is presented and some therapeutic implications, specifically the adverse effect of PEEP in such situations, are discussed.

Observer reliability in CT and MRI of the abdomen/pelvis.

The purpose of this research was to evaluate two sources of error in the performance of computerized tomography (CT) and magnetic resonance imaging (MRI) of the abdomen/pelvis. The sources of error assessed were inter- and intra-observer reliability. Thirty abdomen/pelvis CT scans were randomly selected from each of three hospitals (university, VA, military) with different CT scanners. Two radiologists were recruited from each site to be CT observers. Forty-five abdomen/pelvis MRI scans were randomly selected from two institutions with different MRI scanners. Four observers were recruited to read the MRI scans. All scans were read blind without clinical information or patient identification. Overall inter-observer and intra-observer diagnostic agreement was significantly higher for MRI compared to CT. Inter-observer diagnostic agreement rates were also significantly higher for MRI when the etiologies of neoplastic vascular and metabolic/toxic were assigned. Observer experience in CT (range: 5-9 yr) or MRI (range: 2-4 yr) was not statistically associated with improved diagnostic agreement. This research addresses many of the criticisms of the MRI literature and compares MRI favorably to CT.

Computed tomography demonstration of inferior lumbar (Petit's) hernia.

Inferior lumbar (Petit's) hernia is an uncommon condition resulting from a defect in the posterior abdominal wall. Such hernias may be difficult to diagnose on the basis of physical signs and symptoms. A case of unsuspected inferior lumbar hernia clearly demonstrated by computed tomography (CT) is presented. Computed tomography is useful in determining the size and contents of the hernia, permitting accurate diagnosis, and planning treatment.

Increased renal parenchymal accumulation of Tc-99m HDP in kidney contusion.

Unilateral focal areas of intense, increased renal uptake of Tc-99m oxidronate sodium (technetium-99m HDP) were incidentally detected in the bone scan of a female patient who subsequently gave a history of recent trauma to her flank. Increased renal parenchymal uptake of Tc-99m HDP in this patient was thought to be due to kidney contusion. The case is interesting in itself and for its possible implications regarding the use of radio-labeled phosphate compounds for detection of renal contusion.

Cholecystosonography in diagnosis of cholelithiasis--pathologic and radiographic correlation.

Ultrasound examinations of 140 patients with a clinical suspicion of gallstones were compared with radiographic, surgical and pathologic findings to determine the accuracy of cholecystosonography. Ultrasound was 95% accurate for gallbladder disease, with a 5% false negative rate. Oral cholecystography was 96% accurate. The abnormal ultrasound examinations were divided into three groups, as described by Crade. Group 1 -- shadowing echoes within the gallbladder which move with gravity -- was 100% accurate for gallstones. Group 2 -- non-visualization of the gallbladder with acoustic shadowing -- was 94% accurate for gallstones. Group 3 -- non-shadowing echoes within the gallbladder -- was only 59% accurate for gallstones, but 96% accurate for gallbladder disease. We recommend cholecystosonography as the initial study in the investigation of gallbladder disease.

Accuracy of sonography and transhepatic chloangiography in obstructive jaundice.

Fifty patients with obstructive jaundice were studied by both ultrasonography and percutaneous transhepatic cholangiography (P)TC). Comparison was made of the relative accuracy of sonography and transhepatic cholangiography in delineating both the site and cause of the jaundice. The site of obstruction was defined in 86% by sonography and in 100% by PTC. Etiology was defined in 52% by sonography and in 86% by PTC. Using both modalities the etiology was evident in 94% of patients. Percutaneous transhepatic cholangiography should be reserved for those patients in whom sonography does not identify the site and cause of the obstruction.

Ultrasonography in evaluation of the jaundiced patient.

We evaluated 105 patients with jaundice by greyscale ultrasound. Of these, 66 were proven to have extrahepatic obstruction and 39 had hepatocellular jaundice. The overall accuracy of sonography in distinguishing intrahepatic from extrahepatic jaundice was 93%. Intrahepatic ductal dilatation was identified by sonography in 46 of 49 patients (94%). In 26% of patients with extrahepatic obstruction there was only dilatation of the common duct and no intrahepatic bile duct dilatation. Sonography is recommended as the imaging procedure of choice in the initial investigation of the jaundiced patient.

Avascular bone necrosis in an untreated case of chronic myelogenous leukemia.

Hip pain due to aseptic necrosis of the femoral head was the first clinical manifestation of chronic myelogenous leukemia in a 9-year-old white female. An erroneous diagnosis of rheumatoid arthritis was first entertained. Physical examination showed splenomegaly, complete blood count revealed leucocytosis of 359,000. The initial radiograph of the involved hip was negative. Biopsy revealed aseptic necrosis of the femoral head. Chronic myelogenous leukemia (CML) was diagnosed on the basis of the peripheral blood smear and bone marrow biopsy. Two months later, radiograph, radionuclide bone scan, and magnetic resonance imaging (MR) of the involved hip were positive for aseptic necrosis of the femoral head.

Bone marrow biopsy changes in the iliac bone mimicking multiple colonic polypi.

Many different entities simulating colonic polyps on barium enema examination have been described. Of the extraluminal mimics, round bony structures such as vertebral pedicles are perhaps best known. We describe the cause of a previously undescribed artifact: bone marrow biopsy of the ilium.

Rupture of a normal spleen caused by vomiting following a metrizamide myelogram.

A case of rupture of a normal spleen caused by vomiting following a metrizamide myelogram is presented. The pathological, clinical and radiological features are similar to those found in traumatic splenic rupture. It is important to be aware that the normal spleen can be ruptured by relatively minor trauma as delay in diagnosis and treatment result in high morbidity and mortality.

Synchronous multicentric desmoid tumors (aggressive fibromatosis) of the extremities.

Synchronous multicentric aggressive fibromatosis does not appear to have been previously reported. Two such cases are described. The tumors were identified by magnetic resonance (MR) imaging. The incidence of synchronous multicentric aggressive fibromatosis is not known. It is anticipated that increased use of coronal MR imaging will reveal more tumors of this type, both synchronous and metachronous. In a patient with known or suspected aggressive fibromatosis, every other soft tissue nodule or mass in the same limb has to be regarded as an additional tumor of the same histology.

Intravenous self-administration of metallic mercury.

Embolization of metallic mercury is extremely rare. The literature has consisted primarily of scattered case reports. Two cases of patients with mercury embolization are presented. The differential diagnosis of the chest radiograph is discussed.

Computed tomography diagnosis of Spigelian hernia. Case report.

Spigelian hernia is a rare hernia which is infrequently diagnosed prior to operations. We report a case of this hernia which was diagnosed by CT preoperatively.

The value of abdominal computed tomography in the pre-treatment assessment of small cell carcinoma of the lung.

Computed tomographic (CT) scans of the abdomen were obtained in 65 patients with biopsy-proved but untreated small cell carcinoma of the lung. Intra-abdominal metastases were found in 24 (37%), the majority being in the liver and adrenals. Abdominal CT before treatment is recommended as a part of the staging process in patients with small cell carcinoma of the lung, since extent of disease is relevant to prognosis.

Xeromammographic diagnosis of mammary hamartoma.

A mammary hamartoma was diagnosed by xeromammography prior to surgery.

CT diagnosis of adenocarcinoma of the appendix.

We report the CT findings in a patient with adenocarcinoma of the appendix. Previously reported cases are reviewed, and a CT appearance which is suggestive of adenocarcinoma of the appendix is presented.

Computed tomography of omental liver packs.

Hypodense liver lesions with attenuation coefficients indicative of fat density were seen on CT of three patients followed up for suspected metastatic spread of gastrointestinal malignancy. Knowledge of previous hepatic surgery using omental packing for hemostasis in the setting of liver trauma or lobectomy was useful in preventing a false-positive interpretation of postoperative complications.

Pancreatic transplantation: scintigraphy, US, and CT.

Twenty-one patients with insulin-dependent diabetes mellitus received simultaneous renal and segmental pancreatic transplants. A retrospective analysis of 112 real-time ultrasound (US) images, 108 technetium-99m glucoheptonate scinti-scans, 55 computed tomography (CT) scans, and 11 cystograms was performed. Complications that were observed included pancreatic transplant rejection, pancreatitis, arteriovenous occlusions, hemorrhage, abscesses, and extravasation at the pancreaticocystostomy site. Scintigraphy is a sensitive indicator of normal transplant function but is non-specific when findings are abnormal. Real-time US aids in the differentiation of acute rejection from pancreatitis and arteriovenous occlusion. CT is helpful for evaluation of postoperative complications. Imaging may play an important role in the noninvasive management of pancreatic transplants.