Using sector endoluminal ultrasound to identify the normal pancreas when axial computed tomography is falsely positive.

RATIONALE AND OBJECTIVES: Little has been reported on the ability of endoluminal ultrasound (EUS) to identify a normal pancreas after an abnormal axial computed tomogram (CT). Many clinicians still use axial technology, as opposed to helical or spiral CT, which differ in scanning speed. Spiral CT and EUS are considered equal in their ability to diagnose pancreatic tumors. Although this is not the case with axial CT, the complementary role by EUS has not been defined. This study reports on the ability of EUS to identify the "true-negative" pancreas deemed abnormal by axial CT. METHODS: Sixty-five consecutive patients suspected of having a small pancreatic lesion were studied by comparing axial CT and EUS examinations, using each patient as his or her own control. Identification of a normal pancreas was reviewed using surgery, biopsy, and long-term clinical follow-up as the standard of truth. RESULTS: Thirty-three patients were documented as having small pancreatic lesions; the remaining 32 were normal. The sensitivity and specificity, respectively, were 91% and 41% for axial CT and 88% and 88% for EUS. The positive and negative predictive values, respectively, were 61% and 82% for CT and 88% and 88% for EUS. The statistical differences between axial CT and EUS were significant. CONCLUSION: An axial CT positive for a small pancreatic mass requires confirmation with additional imaging before invasive management. The specificity of EUS--twice that of CT--is strong evidence that EUS can fulfill this role. Review of the literature supports the conclusion that EUS should be required in the workup of small pancreatic lesions identified at axial CT.

Internal mammary silicone lymphadenopathy mimicking recurrent breast cancer.

This case describes a unique complication of silicone breast implantation that is previously undocumented. Internal mammary silicone lymphadenopathy mimicking breast cancer recurrence represents an important new clinical entity. The diagnosis and management of this clinical enigma are challenging. In our patient, videothoracoscopy proved to be minimally invasive and allowed complete resection of the entire chain of pathologic nodes. Explantation of the silicone prostheses and complete capsulectomy are indicated. Light microscopy alone can suggest the diagnosis of silicone lymphadenopathy. Infrared spectral analysis can be a helpful adjunct to allow an unequivocal diagnosis.

Computed tomographic enteroclysis: one methodology.

RATIONALE AND OBJECTIVES: Computed tomography (CT) is limited in the assessment of partial small bowel obstruction (SBO). Enteroclysis is preferred but gives little direct information about the bowel wall, mesentery, or remote findings. Preliminary results of a combined CT enteroclysis (CT-E) methodology are reported. METHODS: Forty-eight patients with suspected partial SBO underwent a water soluble contrast enteroclysis followed immediately by CT. Pump rates at fluoroscopy and CT were 75 to 100 cc/min unless a high-grade obstruction was encountered at fluoroscopy. Shrake's criteria for complete, high-grade or low-grade partial SBO were used. RESULTS: The calculated dose per patient was 27 rad for CT-E as opposed to 32 rad with traditional enteroclysis. Site specific sensitivity and specificity for low-grade partial SBO, were 82.1% and 87.5%. One death was encountered in a patient with diffuse abdominal metastatic disease and complete obstruction. This was caused by vomiting and aspiration secondary to tube placement alone, CT-enteroclysis having been aborted. CONCLUSIONS: Computed tomographic enteroclysis is a diagnostic option for evaluation of low-grade partial SBOs. Pitfalls with this technique are encountered in decompressed torsions and hernias.

Comparison of sinus x-rays with computed tomography scans in acute sinusitis.

OBJECTIVE: To determine the sensitivity and specificity of sinus x-rays of patients clinically diagnosed as having acute sinusitis. METHODS: Thirty consecutive adult, nonpregnant emergency department (ED) patients clinically diagnosed as having acute sinusitis and meeting study criteria were entered into the study. Sinus x-rays were obtained immediately after study entry and sinus computed tomography (CT) scans were done within 72 hours. Radiologic criteria for sinusitis were defined as more than 3 mm of mucoperiosteal thickening (MPT), an air/fluid (A/F) level, or opacification. All films were read in a blinded fashion [CT scans by two radiologists and plain film by two emergency medicine (EM) staff members and the same radiologists]. A third radiologist 'interpreted Ct scans when the initial radiologists disagreed. RESULTS: Sinus CT scans were obtained for 29 of 30 patients. Radiologists interpreted 28 of 29 CT scans identically, with 21 being positive for sinusitis. Sensitivity and specificity of x-rays were 57% and 88%, 62% and 88%, 67% and 75%, and 48% and 100% for the two radiologists and the two EM physicians, respectively. Four ethmoid, five frontal, and five sphenoid sinuses were opacified or had A/F levels on CT scan. No ethmoid, frontal, or sphenoid sinus was interpreted as being opacified or having an A/F level on plain film. Sensitivity and specificity of maxillary sinus opacification or A/F level on x-ray were 70% and 100%, and 70% and 100%, and 70% and 96%, and 70% and 96% for the two radiologists and the two EM physicians, respectively. Mean concordances (kappa) of x-ray and CT scan interpretations for the four reviewers were 0.34 (range, 0.30-0.39) for the diagnosis of sinusitis and 0.77 (range, 0.74-0.79) for maxillary sinus opacification or A/F level. CONCLUSIONS: Sinus x-rays are less sensitive than sinus CT scans for demonstration of radiographic changes consistent with acute sinusitis. Sinus plain films may not be reliable enough to assist with clinical decision making. If severity of patient illness requires diagnostic certainty, more sensitive imaging studies, such as CT scans of the sinuses, should be considered.

Bilateral diabetic thigh muscle infarction.

A 19-year-old woman with insulin-dependent diabetes mellitus developed pain and tenderness in the medial aspect of the left thigh and calf, followed 1 week later by similar symptoms in the right leg. Technetium 99m pyrophosphate (PYP) radionuclide scans showed increased flow and uptake in the medial thigh muscles. Magnetic resonance imaging (MRI) of the thigh showed increased signal on proton density and T2-weighted images in the medial and lateral thigh compartments. High-resolution B-mode ultrasound showed hyperechoic changes in the anteromedial thigh muscles, with loss of normal myofascial interfaces, and a mixed appearance, bilaterally. Two months later, after the symptoms had begun to resolve, the images had improved. This case documents bilateral diabetic thigh infarction identified by abnormal technetium 99m PYP flow studies, MRI signal, and B-mode ultrasound imaging.

A simple method for producing a technetium-99m-labeled liposome which is stable in vivo.

A new method for labelling preformed liposomes with technetium-99m (99mTc) has been developed which is simple to perform and stable in vivo. Previous 99mTc-liposome labels have had variable labeling efficiencies and stability. This method consistently achieves high labeling efficiencies (greater than 90%) with excellent stability. A commercially available radiopharmaceutical kit--hexamethylpropyleneamine oxime (HM-PAO)--is reconstituted with 99mTcO4- and then incubated with preformed liposomes that encapsulate glutathione. The incubation takes only 30 min at room temperature. Liposomes that co-encapsulate other proteins such as hemoglobin or albumin, in addition to glutathione, also label with high efficiency. Both in vitro and in vivo studies indicate good stability of this label. Rabbit images show significant spleen and liver uptake at 2 and 20 h after liposome infusion without visualization of thyroid, stomach or bladder activity. This labeling method can be used to study the biodistribution of a wide variety of liposome preparations that are being tested as novel drug delivery systems. This method of labeling liposomes with 99mTc may also have applications in diagnostic imaging.

SPECT gallium-67 scanning in early human immunodeficiency virus (HIV) infection. Failure of scanning abnormalities to correlate with immunologic staging.

The use of gallium scanning in the treatment of patients with AIDS has been well described. In this study, 27 HIV-infected patients (Walter Reed Staging Classification I-V) with normal chest roentgenograms were evaluated to determine the occurrence of thoracic gallium abnormalities in early HIV infection. SPECT was used for gallium scanning. Patients received gallium injection on day 1 and bronchoalveolar lavage on day 2, and scanning was performed on day 3. Twenty-eight scans in 27 patients were performed. Mean nodal SPECT activity was compared with corresponding values for lung parenchyma, bronchoalveolar lavage cell counts, and peripheral blood T4 lymphocyte counts. No relationship between nodal and parenchymal activity and cell counts was observed. Although visual scan interpretation was unaffected, gallium activity was significantly increased in the region of bronchoalveolar lavage compared with uptake in other lung regions. It is concluded that SPECT gallium scanning demonstrates significant gallium avidity in recently lavaged lung areas, although no impact on visual scan interpretation was seen. Further, no correlation was seen between the degree of nodal uptake and the immunologic status of these patients with early HIV infection.

Efficacy of follow-up bone scans in carcinoma of the prostate.

Three hundred fifteen radioisotopic bone scans ranging from initial scan only to nine scans per patient, performed on 114 patients with adenocarcinoma of the prostate between 1979 and 1984, were reviewed. Seventeen patients had positive scans, ten on initial scan and seven at follow-up. Nine patients had bone pain at the time of the first positive scan and pain developed in two patients 6 months and 2 years later, respectively. The other six patients are still asymptomatic 1 to 4 years later. False-positive scans were found in six other patients. No patient with bone pain had a negative scan. We believe that routine bone scans for prostate cancer follow-up are not cost-effective unless the patient is symptomatic. Bone scans also are indicated for initial staging and to observe disease response to protocol treatment.

A categorical course curriculum for radiology residencies.

A categorical course curriculum was introduced at Brooke Army Medical Center to focus the content of daily conferences and lectures according to radiology subspecialties. Our goal was to improve the traditional uncoordinated conferences and apprenticeship approach to resident learning. After one-year's experience, resident performance has improved, and residents and staff greatly prefer this style of teaching. The format has been adopted.

Muscle necrosis in the extremities: evaluation with Tc-99m pyrophosphate scanning--a retrospective review.

A retrospective review was done of 34 extremities studied between 1981 and 1985 with technetium-99m pyrophosphate scanning; 22 were subsequently amputated. Results of detailed pathologic examination or immediate postoperative examination of the resected extremity were available in 16 cases. In these cases, scanning had allowed correct prediction of the level of amputation and of the specific areas of muscle infarction in 13 cases. In the one case in which amputation was performed for infection rather than muscle necrosis, the lack of necrosis was correctly predicted with the scan. The limited results of this study indicate that the Tc-99m pyrophosphate scan allows the location of necrotic muscle to be predicted accurately and may therefore be a useful adjunct in determining the best level for ultimate amputation. Special caution is required in those cases in which muscle necrosis is due to acute causes (e.g., traumatic thrombosis) rather than chronic vascular disease.