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.

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.

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.

Diagnostic accuracy of a teleradiology image transmission system.

Teleradiology is the remote interpretation of digitized radiographic images by physicians. The images are usually transmitted over telephone lines, but satellite communication has also been used. The interpretability of the transmitted image is an important factor in the operation and use of teleradiology systems. Commercially available equipment has certain built-in functions that may enhance the interpretability of the image received. These functions and their usefulness in diagnosis are described. It is also possible to enhance the image for transmission, prior to digitizing, by certain manual techniques. These may be of value in situations where the first transmission is lacking in some quality. A test of these functions and techniques is reported.

Computed tomographic evaluation of paraesophageal hernia.

Paraesophageal hernias are relatively rare compared to the more commonly diagnosed sliding hiatus hernia. They tend to be asymptomatic initially, but may gradually enlarge and present with life-threatening complications. The treatment is surgical reduction, preferably as an elective procedure. Computed tomography (CT) clearly demonstrates a paraesophageal hernia through a widened esophageal hiatus, often as an incidental finding, and accurately documents the size, contents, and orientation of the herniated stomach within the lower thoracic cavity. In this report, the CT appearance of 4 patients with paraesophageal hernias is described along with a discussion of this uncommon but important surgical condition.

Innocuous gas collections in pancreatic allografts demonstrated by computed tomography.

Over a 4-year period, 6 pancreatic abscesses were found in 37 patients who had combined renal and segmental pancreatic transplants. An additional 4 patients who were nontoxic at the time of their computed tomographic (CT) examinations had innocuous gas collections, either in the pancreatic allograft or the surrounding peripancreatic tissue. The possible etiology of this gas formation is discussed. These collections do not have the same ominous clinical significance as would be expected in abscess formation. Radiological evaluation should include examination of the gastrointestinal tract and voiding cystograms to detect fistula formation. Simultaneous percutaneous aspiration of this area should be performed to rule out an infective process. If this is negative in a nontoxic transplant patient, the radiologist will be in a position to obviate unnecessary surgical intervention.

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.

Neutropenic colitis: evaluation with computed tomography.

The computed tomography findings of 10 patients with neutropenic colitis are described and illustrated. Seven of these patients had leukemia, one had lymphocytic lymphoma, and two had systemic lupus erythematosus. All patients had colon wall thickening which was either isodense with the normal bowel tissue or showed areas of intramural low density. Air in the thickened bowel wall was seen in six patients. These computed tomography findings in neutropenic patients with fever, abdominal pain, and diarrhea should suggest the diagnosis in most instances, resulting in prompt treatment of this usually life-threatening entity.

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.

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.

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.

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.

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.

Peripheral veno-lymphatic communications.

Though there have been a number of articles on lympho-venous anastomoses, there have been no reports of the opposite situation, namely veno-lymphatic communication. A case of veno-lymphatic communication is presented, and possible explanations for this finding are described.

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.

Computed tomography in the pretreatment assessment of carcinoma of the cervix.

Fifty-nine patients with primary or recurrent carcinoma of the cervix were evaluated by computed tomography as part of their presurgical evaluation. The computed tomography staging results were compared with the surgical staging. Computed tomography staging was accurate in 71% (42 of 59), whereas clinical staging was accurate in 66% (39 of 59). In assessing paraaortic nodes by CT, there were 10 true-positive, 20 true-negative, 1 false-positive, and 2 false-negative results (sensitivity, 83%; specificity, 95%), for an overall accuracy of 91%. For pelvic nodes, there were 10 true-positive, 11 true-negative, 3 false-positive, and 6 false-negative results (sensitivity, 62.5% specificity, 78%), for an overall accuracy of 70%. Excretory urograms and barium enemas provided no information not obtained by computed tomography and are probably unnecessary if computed tomography is used as a routine staging examination. At present, computed tomography should not replace clinical assessment of extent of the disease. Its chief advantage over clinical staging is its ability to detect metastases beyond the true pelvis.

Radiographic and CT demonstration of mammary emphysema.

The radiographic and CT appearance of air within the mammary parenchyma is described along with a discussion of the possible routes of dissection of gas from regions of subcutaneous emphysema into the breast tissue.