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Sixty-eight patients, who were determined clinically (by the presence of audible and palpable-joint sounds) and arthrographically to have meniscus displacement with reduction, had protrusive splints constructed, and the results were evaluated for a minimum of 1 year to a maximum of 3 years. Eighteen additional patients, arthrographically determined to have meniscus displacement with reduction, served as a nontreatment group for comparison. Odds ratios were calculated to compare the proportions of subjects who experienced follow-up symptoms on the two regimens. Results indicated that with splint therapy there was a statistically significant reduction of the intensity of jaw joint pain, temporal headache, ear pain, and pain in front of the ear, and there was a decrease in the probability of a closed lock condition developing. Splint therapy is less likely to reduce frontal headache, neck pain, and clenching of teeth.

The choice between high cost, low toxicity nonionic contrast media (CM) and low cost ionic CM poses a dilemma for radiologists. Ioxilan, a third generation nonionic CM, is obtained by simple conversion from an ionic CM. To examine how this economically promising, low osmolality CM (570 mOsm at 300 mgI/ml) affects canine systemic and renal hemodynamics, IV bolus injections of 350 mgI/ml at 2 ml/kg of Iohexol and Ioxilan were compared. Satisfactory nephrograms and pyelograms were produced by both agents, without significant differences. The effects on systemic and renal hemodynamics were minimal and statistically equal for both CM. The acute systemic and renal responses and radiographic image quality of Ioxilan and Iohexol confirm that the two compounds are biologically equivalent, and that the novel molecular design employed in Ioxilan to achieve very low osmolality also provides good biological tolerance.

This clinical-arthrographic investigation compares power spectral analysis of temporomandibular joint sounds with different arthrographic characteristics of intracapsular dysfunction. The quantitative comparison of specific parameters of the sound power-spectrum waveform may provide a sensitive and accurate noninvasive tool for diagnosis and treatment.

A technique of obtaining direct sagittal (lateral) CT images of the temporal bone is described, and the normal sagittal CT landmarks are illustrated. Using this technique, structures seen to advantage by lateral polytomography may now be imaged by CT. The ability to scan the temporal bone in the sagittal plane should be a useful adjunct to coronal and axial images.

The findings in 308 TMJ arthrograms (280 patients) with selective contrast injection into the inferior compartment are described. An anteriorly luxated meniscus was diagnosed in 231 cases (75%). In 99 cases (32%) the meniscus returned to a normal position spontaneously during opening of the mouth, whereas in 132 cases (43%) the subluxation was permanent. In 108 patients (6%) with irreducible meniscus luxation, perforation of the meniscus or of the capsule was diagnosed, but in two cases this could not be confirmed at operation. The importance of early diagnosis for optimal treatment is discussed.

Investigations into the nature of severe and fatal reactions to contrast media have been severely limited by their unpredictable occurrence in the clinical setting and the absence of suitable laboratory models. The authors report their experience with a canine dehydration model. Intravenous administration of 2 ml/kg of 76% sodium methylglucamine diatrizoate resulted in vomiting, shock, inappropriate slowing of the heart rate, and death. ECG findings indicated suppression of sinoatrial node automaticity, a decrease in the rate of atrioventricular conduction, and depression of myocardial contractility. These results suggest two possible mechanisms: (a) enhanced vagal tone as the result of stimulation of the vasomotor center of the medulla or (b) accentuation of direct contrast-induced myocardial toxicity.

Temporomandibular joint (TMJ) dysfunction may cause facial or aural pain. Conventional roentgenograms are useful to define bony pathologic conditions. However, TMJ arthrotomography may disclose joint meniscus abnormalities in two thirds of patients with persistent dysfunction despite normal roentgenograms.

The osmotic effects caused by conventional and low osmolality radiopaque agents have been studied in the isolated perfused canine kidney. Changes in vein flow, hematocrit, osmolality, and iodine content were measured at injection doses of 0.25 and 0.5 ml/kg (300 mgI/ml). Increases in osmolality and decreases in hematocrit were significantly greater with the conventional ionic monomer meglumine/sodium diatrizoate than with the low osmolality agents iohexol, iopamidol, and ioxaglate. The standard renal vein flow response for all agents was an increase (loss of renal water) followed by a decrease (gain of renal water). Diatrizoate produced the greatest increase in outflow at 0.25 ml/kg, but the differences between agents were not statistically significant. At the 0.5 ml/kg dose the differences in peak renal vein flow between agents were negligible. Renal vein iodine was highest with the dimer, ioxaglate and lowest with the diatrizoate. The nonionics iohexol and iopamidol produced essentially the same renal vein iodine levels and clearance. The new low osmolality agents have significantly less effect on osmolality and hematocrit and produce higher venous iodine levels than a conventional ionic monomer. The only difference between the low osmolality agents was the higher venous iodine seen with the dimer ioxaglate.

CT and MR imaging have been advocated for use in the diagnosis of disorders of the temporomandibular joint. A systematic comparison of these imaging techniques has not been made. We performed direct sagittal CT and sagittal MR on 15 fresh temporomandibular joint autopsy specimens and compared our diagnoses with cryosectional findings in a blinded fashion. We found no statistically significant differences between these procedures in detecting bony abnormalities or disk position. However, a side-by-side comparison between the CT and MR images demonstrated that MR depicted the soft-tissue anatomy of the joint with greater detail than did CT. Thus, MR clearly displayed the disk when it was positioned either superiorly or anteriorly, whereas CT only showed the disk adequately when it was positioned anteriorly. MR further showed the configuration of the disk and the borderlines between the disk and its attachments; these relationships could not be assessed from CT images. This experimental study indicates that MR is superior to CT for depiction of soft-tissue changes, whereas CT is superior in showing osseous abnormalities. Clinical confirmation of these results is necessary before one method can be definitively recommended over the other for clinical studies.

This clinical-arthrographic investigation correlates arthrographic characteristics of intracapsular dysfunction of the temporomandibular joint with sound analysis. Sound patterns may provide a noninvasive tool for diagnosis and treatment.

This report describes early experience with magnetic resonance imaging (MRI) of the temporomandibular joint meniscus in which surface coil technology was used. The results suggest remarkable imaging capabilities and speed with noninvasive methods.

Ninety-seven patients who were undergoing excretory urography for suspected genitourinary tract abnormalities were continuously monitored for systemic blood pressure and pulse rates before (control) and after rapid intravenous injections of contrast material (1.5 ml/kg meglumine iothalamate, 60%) using a Bard pressure monitor. We report the systemic responses observed. Clinically obvious reactions to contrast medium were recorded and compared with the blood pressure and pulse rate responses. The most common response to rapid infusion of contrast medium was a transient hypotension. An increase in systemic pressure had a high association with nausea and vomiting. Significant hypotension (mean blood pressure less than 60 mm Hg) was observed in six patients (6%), but no overt clinical manifestations were present.

Radiographic contrast media (CM) (meglumine/sodium diatrizoate-76%; 1650 mOsm/kg) and other hypertonic solutions induce renal vasoconstriction by an unknown mechanism. In anesthetized dogs, renal blood flow (RBF) was measured with an electromagnetic flowmeter and filtration fraction (FF) and glomerular filtration rate (GFR) by the renal extraction of technetium-99m tin chelate. Ureteral pressure (UP) and wedged renal venous pressure (VP) were measured as indices of intrarenal pressure. Measurements of renal length (L), along with pressures, made it possible to examine the compliance of the system. A 4-cc intrarenal bolus of CM caused a 59% reduction in GFR (control: 0.63 +/- 0.04 to 0.26 +/- 0.04 ml/min X g, mean +/- SEM), in association with a 23% reduction in RBF (control: 3.10 +/- 0.11 to 2.39 +/- 0.26 ml/min X g) and a 44% decrease in FF (control: 0.32 +/- 0.01 to 0.18 +/- 0.03). These responses were compared with a 3-microgram intrarenal bolus of norepinephrine (NOREPI) which resulted in a 79.0 +/- 7.5% reduction in RBF, 68.3 +/- 7.3% reduction in GFR and 42.6 +/- 15.6% increase in FF. The NOREPI-induced vasoconstriction caused transient decreases in renal L, UP, and VP, whereas the CM-induced decrease in renal blood flow was associated with increases in these parameters. In studies employing ureteral occlusion to elevate intrarenal pressure, the magnitude (area, cm2) of the CM-induced decrease in renal perfusion was accentuated with increased UP (r = 0.79, n = 24, P less than 0.001). The CM-induced increase in renal L, UP, and VP must reflect osmotic forces and an increase in intrarenal pressure. The decreases in FF and GFR probably reflect Starling forces in the glomerular capillaries, with osmotic transients dominating. The results suggest a mechanical mechanism for the CM-induced decrease in RBF.

The arthrographic findings in 141 patients with TMJ symptoms were compared with the linear tomographic evaluation to assess the incidence and severity of associated osseous abnormalities. Thirty-nine temporomandibular joints (28%) had significant osseous abnormalities compatible with degenerative joint disease. The incidence and severity of the degenerative changes compared favorably with the arthrographic assessment of the degree of soft-tissue injury. A cause-and-effect relationship between TMJ disc damage and dysfunction and degenerative arthritis is suggested.

Most abnormalities in the T.M. joint are due to pathological processes in the meniscus or joint capsule. They usually manifest themselves as an anterior luxation of the meniscus, which cannot be demonstrated by conventional radiological examination, even including tomography. In order to evaluate the meniscus, it is necessary to perform a contrast examination of the inferior joint space. The technique has proved valuable in 280 patients (308 arthrograms). The method is described and radiological anatomy is discussed. There were no significant complications in our series.

Two hundred five patients were examined for temporomandibular joint pain and dysfunction and specifically for tenderness to muscle palpation. Arthrograms were performed on 222 joints (188 unilateral and 17 bilateral). Significant findings were ascertained for the middle portion of the temporal muscle in "normal" patients versus "with and without meniscus reduction" patients. The superficial masseter muscle was more tender in "normal" patients and in "reducing meniscus" patients than in "without meniscus reduction" patients. The medial pterygoid muscle was more tender in "normal" patients and in "without meniscus reduction" patients than in "reducing meniscus" patients. Though there are some significant findings with respect to muscle palpation, by itself muscle palpation is not a specific indicator of temporomandibular joint internal derangement.

Intrarenal angiotensin (AII) infusion results in a poorly sustained renal vasoconstrictor response. To examine the relationship between fade and renal tachyphylaxis to AII, sub-pressor doses of AII and norepinephrine (NE) were injected into the renal arteries of anesthetized dogs, resulting in a transient reduction (greater than 50 percent) in renal blood flow. Continuous intrarenal AII infusion, sufficient to reduce renal blood flow by 50 percent, followed. Within five minutes, despite continued AII infusion, substantial recovery (73 +/- 11 percent) of renal blood flow occurred; however, the response to AII bolus injection was lost, but that to NE was sustained. A second group of dogs received indomethacin (5 mg/kg intravenously) 30 minutes prior to the study; the reduction in renal blood flow was better sustained; however, renal tachyphylaxis was still evident.

Three cases of "shock kidneys" were demonstrated by excretory urography. A dense, prolonged nephrogram and decreased excretion of the contrast material during the hypotensive episode were seen. In addition, our cases show bilaterally small kidneys without evidence of underlying chronic renal disease, which we consider to be a normal physiologic response.

Fifty one subjects who had pain involving the temporomandibular joint were evaluated using multidirectional tomography, arthrography, conventional nuclear scanning, and single photon emission computed tomography (SPECT) to assess the association of arthritis of the temporomandibular joint with internal derangements related to meniscal dysfunction. Five (56%) of the nine subjects who had normal arthrograms and normal multidirectional tomograms had SPECT scans that were positive for osseous changes. Twenty-two subjects (27 temporomandibular joints) were diagnosed by arthrography to have meniscal displacement with reduction. Multidirectional tomograms of the 27 joints were positive for osseous changes in five (18%) joints, whereas SPECT scans were positive in nine (70%) joints. Twenty subjects (20 temporomandibular joints) had an arthrographic diagnosis of meniscal displacement without reduction. Multidirectional tomograms of the 20 joints were positive for osseous changes in 14 (70%) joints, and SPECT scans were positive in 16 (80%) joints (P less than 0.001 vs control group). Initial observations with SPECT indicate it is a promising imaging method for detecting and staging osseous disease of the TMJ related to meniscal dysfunction.

We report a series of four patients presenting with symptoms of temporomandibular joint pain and dysfunction, and manifesting calcified loose bodies within the temporomandibular joint. Tomographic and arthrotomographic findings are described. Surgical confirmation was obtained in two patients and the histopathology in one demonstrated that the loose body was calcified cartilage surrounded by synovial tissue. The synovial tissue of the joint space was normal in all four cases by arthrotomography and at surgery in two patients. The findings suggest that these cases may be examples of osteochondrosis dissecans.

We made MR images of 39 autopsy specimens of the temporomandibular joint at 0.3 and 1.5 T and compared the images with anatomic cryosections. Imaging time and slice thickness were the same on scans made at each field strength. The purpose was to determine which field strength provides the best scans for imaging of the joint. Additionally, we used imaging times two and four times longer on the 0.3-T scanner to assess to what extent image quality and diagnostic accuracy could be improved. The cryosections showed that 27 of the joints were normal. Twelve had disk displacements. Ten of the joints with disk displacement also had disk deformities, and seven had bony abnormalities. Investigators who analyzed the MR images had no knowledge of the findings on the cryosections. The disk position, disk configuration, and bony abnormalities were correctly diagnosed in 85%, 77%, and 100%, respectively, on 1.5-T MR images compared with 46%, 41%, and 85%, respectively, on the 0.3-T images. When the imaging time was increased by a factor of four, the accuracy rate on the 0.3-T system became comparable to that of the 1.5-T MR scanner: 73% for disk position, 67% for disk configuration. The results suggest that the diagnostic quality of MR images of the temporomandibular joint is better on scans made at 1.5 T than on those done at 0.3 T when comparable imaging times are used.

A double-blind clinical trial was performed in 60 patients to compare Hexabrix (ioxaglate meglumine and ioxaglate sodium) and Renografin-60 (diatrizoate meglumine and diatrizoate sodium). Use of Hexabrix produced higher urinary iodine concentrations, lower urine volumes at 30 minutes, and excretory urograms significantly better in diagnostic quality, as rated by four independent observers. There was no difference in nephrogram quality between contrast agents. Patients receiving Hexabrix had less of an increase in heart rate and demonstrated a slight rise in mean arterial blood pressure, rather than the biphasic rise then fall seen with Renografin-60. There was no significant change for up to 96 hours after urography in results of hematology, clinical chemistry, or urinalysis, except for an increase of 0.005 in urine specific gravity with Renografin-60. Patients reported significantly less body heat, heat in the injection arm, and overall discomfort with Hexabrix. There was a similar amount of nausea and vomiting in the two groups. Hexabrix also caused histaminic-type reactions in three patients.

Pathologic alteration of the articular disk, including moderate calcification within the meniscus proper, has been reported to occur in many cases of TMJ dysfunction with chronic anterior meniscal displacement. The purpose of this investigation was to measure, by means of direct sagittal computed tomographic scanning technology, the density (x-ray attenuation) of the meniscus. Fifty-two joints, shown to have meniscus displacement with or without reduction (MD/MDR), and 24 symptomatic joints with normal tomograms were evaluated with the use of a GE 8800 CT scanner. Mean attenuation values were extrapolated with the use of a symmetrical (1 to 9 pixels) region-of-interest (ROI) cursor. Density gradients of the masseter muscle, lateral pterygoid fat pad, and lateral pterygoid muscle were also obtained. The results of this study showed that the mean meniscal density values were 116.7 +/- 4.2 Hounsfield units (HU) for MD subjects, 111.3 +/- 4.6 HU for MDR subjects, and 82.4 +/- 2.9 HU for subjects with symptoms. The MD and MDR density group means were significantly different (p less than 0.001) from the normal group means. A relative comparison of the meniscus density with that of the lateral pterygoid muscle, its fat pad, and the masseter muscle showed a consistent mean difference when the paired t test was used. Meniscal displacement was found to be associated with an increase in density gradient, which suggests histologic alteration.

The effects of intravenous contrast media (CM) on renal excretory function and subcellular morphology are examined in this animal investigation. A decrease in GFR (12.0 +/- 1.6 vs. control 30.2 +/- 2.5 ml/min) was observed when renal function was evaluated by means of the artero-venous extraction method with Tc99m DTPA and the anticipated inverse relationship to urinary flow (Vml/min) noted. An artifactual increase in GFR (43.5 +/- 10.0 vs. control 39.1 +/- 3.8 ml/min) was observed using the timed urinary clearance of inulin. V(ml/min) increased four-fold (0.6 +/- 0.16 control vs. 2.7 +/- 0.7 ml/min; P less than .05) over the first five minutes after injection of CM. Urine osmolality initially approached isotonicity and then returned toward preinjection values. Osmolal clearance (Cosm) rose 2.5 times (1.4 +/- 0.3 control vs. 3.7 +/- 1.0 ml/min; P less than .05). The fractional excretion of both Na+ (FENa+) and K+ (FEK+) increased. A comparison of urinary osmolality vs. time after injection of CM confirms a nonspecific osmotic effect on tubular (and hence total urine) flow. The hemodynamic effects of CM on the kidney via the i.v. route reflect a predominant and nonspecific osmotically mediated vasodilation. No significant light or electron microscopic changes were observed. These findings suggest that the major renal physiologic actions of hypertonic CM are a nonspecific response to agent osmolality.

The anatomy and function of the temporomandibular joint are complex, and our understanding about how the retrocondylar tissues change when the condyle translates anteriorly has been incomplete. We therefore examined the sectional anatomy of 24 fresh human temporomandibular joints at different gradations of jaw opening, protrusion, and laterotrusion. We found that the tissues of the posterior disk attachment expanded in volume and occupied the space behind the condyle when the mouth was opened, protruded, or laterotruded to the contralateral side. Volumetric expansion of the tissue seemed to be due mainly to distension of the venous structures in the retrodiskal area. In the lateral region of the joint, tissue from the superior aspect of the parotid gland also seemed to contribute to the filling of the space posterior to the condyle. Thus, the retrodiskal tissue appears to have a substantial capacity to expand and fill the mandibular fossa when the condyle translates anteriorly. The possibility of a dynamic vascular physiology is suggested.

Internal derangements of the temporomandibular joint (TMJ) may be a significant factor in the etiology of painful dysfunction of the jaw and associated clinical symptoms. In a two-year prospective investigation, 170 TMJs in 85 patients were studied with plain tomography prior to arthrotomography. Arthritis was detected in 19 patients (22%), predominantly in the second to fourth decade of life, which correlated with internal derangements depicted by arthrotomography, operative findings, and histopathological examination of the condylar surface. The authors suggest that internal derangements related to meniscal dysfunction may be an important factor in the etiology of TMJ arthritis.

Growing concern about acute renal failure as the result of contrast agents prompted an investigation into the renal effects of intravenous contrast materials in euvolemic and dehydrated dogs. Bolus injection of hypertonic agents induced marked reductions in filtration fraction and glomerular filtration rate in both groups of animals; however, these changes were transient, returning to near-base-line values within 30 minutes after injection. The most striking differences between euvolemic and dehydrated animals appeared to be related to prerenal factors such as hypovolemia and contrast-induced hypotension.

The effect of .3 cc of 1:1000 epinephrine on iodine concentration, total iodine content, fluid volume and radiographic quality was evaluated in knee arthrograms in dogs. With the addition of epinephrine the iodine concentration and total iodine content were significantly higher initially and remained significantly higher than in controls over a one hour period. The fluid volume in the knee was significantly lower with epinephrine. Initially both contrast absorption and dilution have major effects in decreasing iodine concentration. With increasing time the effect of contrast absorption becomes the major factor, having a two of three times greater effect on decreasing iodine concentration. With epinephrine radiographs were judged significantly better early and while the quality deteriorated rapidly in the controls the enhanced quality with epinephrine persisted up to one hour. Epinephrine is a very useful adjunct in enhancing the quality of knee arthrography.

Two hundred five patients were prospectively examined for temporomandibular joint pain. Arthrograms were performed on 222 joints (188 unilateral and 17 bilateral). Pain in the ear occurred more frequently in arthrographically normal patients and in nonreducing meniscus patients compared with reducing meniscus patients. The location of pain in front of the ear, in the temples, or in the neck or the degree of pain intensity did not correlate to specific meniscal abnormalities. No correlation between the distribution and the character of headaches was observed. Pain characterization alone does not clinically separate meniscal abnormalities.

We compared patient morbidity associated with temporomandibular joint (TMJ) arthrography using both meglumine/sodium diatrizoate (60%) and the new monoacidic dimer, Hexabrix, in a double-blind randomized clinical trial in 31 patients. Patients experienced maximal discomfort from TMJ arthrography with the initial joint filling and joint distension; this rapidly resolved over 10 minutes. Delayed exacerbation of pain is less than described for shoulder arthrography. The newer contrast media promise to decrease patient morbidity with arthrography.

The objective of this clinical study was to determine the relationship between condylar translation on plain tomographic radiographs and internal derangements assessed by a clinical and arthrographic evaluation. One hundred two joints in sixty-two patients were evaluated by linear tomography in closed versus opened positions and classified according to the type of internal derangement depicted by arthrotomography in sixty-two cases. A decrease in condylar translation was noted in patients diagnosed as having meniscus displacement without reduction. Patients who had meniscus displacement with reduction (painful clicking) were found to have hypermobility of the condyle on the symptomatic side. Meniscus displacement without reduction, which appears to be an advanced stage of internal derangement, is a serious sequela leading to marked restriction of condylar motion.

Selective renal angiography causes a biphasic change in renal blood flow and vascular resistance. In this study, 5 ml of meglumine/sodium diatrizoate (288 mg I/ml, 1455 mosm/kg), metrizamide (290 mg I/ml, 593 mosm/kg), isontonic saline (287 mosm/kg) and hypertonic saline (1500 mosm/kg) were injected into the renal arteries of seven adult mongrel dogs to determine whether the minimum flow (or maximum resistance) was related to the osmolality of the injected agent. The maximum resistance response was significantly smaller for metrizamide (20 +/- 4%) and isotonic saline (19 +/- 2%) than for diatrizoate (36 +/- 6%) or hypertonic saline (50 +/- 7%). Hypertonic saline produced two distinct types of responses: the typical biphasic response or a severe immediate drop in flow. Thus the maximum resistance response was related to agent osmolality. The "injection artifact," or flow changes occurring during the injection, were different for the four agents, and these differences appeared correlated to agent viscosity. Although both contrast media caused relatively small changes in renal hemodynamics, metrizamide caused significantly smaller changes than meglumine/sodium diatrizoate.

During a five-year period, a total of 150 patients (131 girls and 19 boys) with an average age of 14 years (range 7-16 years), with signs and symptoms of temporomandibular joint dysfunction were referred for imaging in the diagnostic radiology department. These patients were evaluated by multidirectional tomography to both joints, arthrography, computed tomography (CT), or magnetic resonance (MR) of one or both joints. Fifty-six (37 percent) of the 150 patients had plain tomographic, CT or MR evidence of degenerative arthritis of one or both sides (18/150 12 percent with bilateral degenerative joint disease). Internal derangements of the TMJ related to meniscal displacements and dysfunction were detected in 128 patients (85 percent). Twenty-nine patients (29/150: 20 percent) suffered from bilateral internal derangements. This clinical study demonstrates that internal derangements do occur in the pediatric age-group: the high percentages of both internal derangements and degenerative joint disease suggest a cautious clinical acceptance of imaging for internal derangements in the young patient. This reluctance to study these patients should be minimized by the new, noninvasive imaging modality available in magnetic resonance.

Image opacification, patients' tolerance, and clinical and laboratory findings were evaluated in patients having excretory urography at three centers. In a double-blind, parallel study, iopamidol was compared with diatrizoate (50-ml dose), and in an open-label trial, the administration of a 100-ml dose of iopamidol was evaluated. In the double-blind study, a total of 84 patients received 50 ml of either iopamidol or diatrizoate. In the open-label study, another 42 patients received a 100-ml dose of iopamidol. Image opacification scores after the administration of the 50-ml doses showed better opacification with iopamidol than with diatrizoate in the renal calices (p less than .05) and in the composite kidney (p less than .05). Opacification scores were higher for 100-ml doses of iopamidol than for 50-ml doses in all anatomic regions as well as in the composite kidney (p = .0001). Patients' tolerance to iopamidol was significantly better than their tolerance to diatrizoate (p less than .025). Investigators observed adverse drug reactions in a total of 10 patients. In the double-blind study, one of 43 patients had transient bradycardia after the administration of iopamidol. In the same study, four of 41 patients who received diatrizoate had five minor adverse drug reactions. With 100-ml doses of iopamidol, five of 42 patients had adverse reactions. No adverse side effects required therapy in either study. There were no significant changes in vital signs or laboratory values after drug administration. The results of this study show that iopamidol is a suitable agent for excretory urography at doses of 50 and 100 ml. Patients report fewer unpleasant side effects with iopamidol than with diatrizoate. Overall image quality was better with iopamidol than with diatrizoate. Overall evaluation of drug performance was better with iopamidol than with diatrizoate.

Two hundred eleven patients with signs and symptoms of temporomandibular joint (TMJ) internal derangements were referred for magnetic resonance imaging. Both TMJs of each patient were routinely evaluated in this prospective investigation. With 422 joints examined, 29% (61) of the patients had bilaterally normal findings, 21% (45) of the patients had one normal side and one abnormal side, and 50% (105) of the patients showed bilateral internal derangements. This clinical study demonstrated a high likelihood of bilateral internal derangements in patients with symptoms of TMJ internal derangements.

Hypertonic solutions, such as contrast media (meglumine/sodium diatrizoate-76%; Renografin-76), induce vasoconstriction in the renal vascular bed via an unknown mechanism. We assessed a possible role of two vasoconstrictor hormones known to be released by the kidney, angiotensin II (AII) and the prostaglandin, thromboxane. Specific inhibition of AII at the smooth muscle receptor level by saralasin (0.33-0.75 microgram/kg/min, IA) did not attenuate the response. Inhibition of prostaglandin formation by indomethacin (4 mg/kg, IV), likewise, did not prevent the decrease in renal perfusion. We conclude that neither AII nor the prostaglandin system mediate the contrast medium-induced renal vasoconstriction.

An uncommon cause of late ureteric obstruction in renal transplants is fibrosis involving the allograft pelvis and ureter. Three new cases are reported, emphasizing a characteristic radiographic appearance of marked generalized narrowing of the renal pelvis and ureter with concomitant dilatation and hydronephrosis of the calyceal system. This unique pattern of obstruction is the result of infiltration of the transplant ureter and pelvis by fibrous tissue. Although the exact stimulus that incites this intense fibrotic scarring is unknown, ischemia, rejection episodes, and infection have been implicated. When properly diagnosed, conservative urologic management, with ureteral stenting and dilatation, is usually adequate to maintain transplant function.

A simplified arthrotomographic technique has been performed successfully in more than 200 patients with symptoms referable to the temporomandibular joint. Soft-tissue abnormalities not detected by plain film radiography were demonstrated. Anterior meniscus displacement was the most significant finding in patients with unilateral pain and limitation of opening. New arthrographic observations and research imaging methods, including CT-assisted arthrography, are described. Leakage of contrast material along the lateral condylar neck in patients with anterior meniscus displacement suggests associated tearing of the lateral capsular attachment. Our results confirm that arthrography is a useful diagnostic procedure for suspected internal derangements of the temporomandibular joint.