Analysis of radiocontrast-induced nephropathy by dual-labeled radionuclide clearance.

RATIONALE AND OBJECTIVES: This study was devised to develop a method of measuring the acute effects of radiocontrast media on renal function and assessing the relationship of the dose of radiocontrast media infused with the incidence of radiocontrast-induced renal failure. In addition, the drug adenosine phosphate-magnesium chloride (ATP-MgCl2) was evaluated as a renoprotective agent. METHODS: Eighteen patients with pre-existing renal impairment, (serum creatinine greater than 133 mumol/L) were randomized to receive a continuous infusion of ATP-MgCl2 or placebo before and during a radiocontrast procedure. Subjects were monitored with daily serum creatinine and with radionuclide renal clearance studies at baseline, during, and 24 hours after the radiocontrast procedure. RESULTS: There was an initial deterioration in renal clearance in the entire study group (from 44.2 +/- 4.6 to 32.6 +/- 3.9 mL/min, P = .001) which was independent of the dose of radiocontrast infused. There was a persistent deterioration in renal clearance only in those who received greater than 135 mL of contrast media (from 48.6 +/- 7.8 to 37.1 +/- 3.9 mL/min, P = .05). There also was an increase in serum creatinine that persisted only in those subjects who received greater than 135 mL of contrast media (230 +/- 27 to 283 +/- 44 mumol/L, P = .01). CONCLUSION: Persistent deterioration in renal function after radiocontrast administration appears to be dose-dependent and is not prevented by the use of ATP-MgCl2. Radionuclide techniques are useful in monitoring acute changes in renal function during radiocontrast procedures and may be of value in assessing renal impairment in future intervention studies.

Embolization of extensive peripheral angiodysplasias. The alternative to radical surgery.

We describe two patients with extensive pelvic and lower limb angiodysplasias, in whom hemodynamic complications subsequently developed. These have been treated by selective angiography and multiple percutaneous transcatheter embolizations with satisfactory results (1 1/2 to four years of follow-up). One patient had had three previous operations with no improvement; amputation was the only surgical alternative. In the other patient, hip disarticulation and hemipelvectomy was seriously considered because of cardiac failure not responding to medical therapy. We review the literature and use our cases to illustrate points of technique and reemphasize the essential role of therapeutic embolization in the management of extensive angiodysplasia.

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.

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.

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.

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.

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 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.

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.

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.

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.

Normal thymus: CT characteristics in subjects under age 20.

The chest computed tomographic (CT) scans of 40 subjects aged 20 or younger were analyzed retrospectively with special attention to the anterior mediastinum and the thymus. Thirty-four of the patients were considered to have normal CT appearances of the anterior mediastinum; neoplasm was suspected at this site in the other six. In the normal group, the gland was consistently identified as a characteristic anterior mediastinal structure. It had smooth, undulating, lateral contours tending to be convex laterally in the very young and concave laterally at an older age, although there was overlap in many in whom the shape of the lateral contours was a combination of convex, concave, or straight. A sharp angular contour to the lateral margin of the thymus was seen occasionally and is also thought to be characteristic of normal thymus. The posterior border of the gland molded to the heart and great vessels in all patients. The anterior contour was molded to the anterior chest wall or had a pointed shape directed toward the sternum. Molding to the mediastinum and chest wall was not found or was present to only a limited degree in the patients with anterior mediastinal tumor. Attenuation values varied between different normal glands and within the same gland on both pre- and postcontrast scans. Recognition of normal variation in the CT appearance of the thymus in young patients may prevent false-positive diagnosis of neoplasm.

Diagnosis of parathyroid adenoma by computed tomography.

A diagnosis of cervical parathyroid adenoma was made at computed tomography (CT) in two patients not initially suspected of having primary hyperparathyroidism. In each case, the lesion appeared as an oval shaped mass indenting and deforming the posterior surface of one lobe of the thyroid gland. In one patient, the lesion was sharply contrasted by iodine-containing thyroid tissue, which appeared denser than the adenoma. The significance of these findings is discussed as well as some of the problems encountered in the CT diagnosis of parathyroid adenoma.

CT diagnosis of venous pseudotumors in the chest and abdomen.

Appearances simulating neoplastic masses were found in five patients undergoing computed tomographic (CT) scanning of the chest and abdomen for a variety of indications. In each case the appearance was shown to be due to dilated collateral venous channels in association with portal hypertension or interruption of the inferior vena cava. The vascular origin of the masses was confirmed by CT scanning during intravenous bolus injection of contrast. Angiographic confirmation was obtained in three subjects. Enlarged collateral veins should be considered in the differential diagnosis of appearances suggesting mediastinal or abdominal lymphadenopathy at CT scanning.

Spina bifida and unilateral focal destruction of the distal femoral epiphysis.

Focal destruction of the postero-lateral distal femoral epiphysis was present on radiographs in two children with spina bifida and objective lower limb sensory loss. Each patient presented with painless swelling of the knee. In one patient the epiphysis showed sclerosis and fragmentation associated with a defect. In the second patient the destructive change was the dominant radiographic abnormality and simulated bone tumor. Computed tomography in this patient showed a bone fragment occupying the defect suggesting epiphyseal fracture. The lesion in each patient was believed to be traumatic in origin and to represent a stage in the development toward neuropathic arthropathy.

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.