Richard W. Katzberg

Anatomic disorders of the temporomandibular joint disc in asymptomatic subjects

PURPOSE This study determined the prevalence and specific anatomic types of disc displacement in asymptomatic versus symptomatic subjects using magnetic resonance imaging (MRI). PATIENTS AND METHODS A detailed MRI assessment was performed on both temporomandibular joints (TMJ) in 76 volunteers and 102 successive patients. Attention was placed on the functional aspects of disc displacement with and without reduction and on the anatomic aspects of disc displacement in the anterior, lateral, medial, anterolateral, and anteromedial directions. These assessments were made by radiologists blinded to the clinical information. RESULTS Disc displacement was found in at least one joint in 25 of 76 (33%) of asymptomatic subjects and 79 of 102 (77%) of symptomatic subjects. The anatomic types of disc displacement between groups was not statistically significant (P = .55). However, there was a significant difference between asymptomatic and symptomatic subjects, with an odds ratio of 3.91 for disc displacement with reduction and 42.71 for disc displacement without reduction (P < .001). CONCLUSION Although there was a 33% prevalence of disc displacement in asymptomatic volunteers, there was a highly significant difference in the prevalence of internal derangement in symptomatic subjects. Bruxing was statistically linked to TMJ disc displacement and could explain the anatomic variation in abnormal disc position.

Frequency of Acute Kidney Injury Following Intravenous Contrast Medium Administration: A Systematic Review and Meta-Analysis

PURPOSE To perform a systematic review and meta-analysis of controlled studies examining the incidence of acute kidney injury (AKI) and other outcomes in patients exposed to intravenous (i.v.) contrast medium compared with patients who underwent an imaging examination without contrast medium or were otherwise unexposed (control group). MATERIALS AND METHODS MEDLINE, EMBASE, Scopus, and the Cochrane Library were searched for all articles published through September 2011 that contained search terms related to nephrotoxicity following intravenous contrast medium administration. Two independent reviewers identified studies in which the incidence of AKI in patients exposed to i.v. contrast medium was directly compared with the incidence of AKI in unexposed patients through analysis of changes in serum creatinine level or estimated glomerular filtration rate 48-72 hours following imaging procedures or admission. Study characteristics and outcomes of AKI, dialysis, and mortality were extracted by using a standardized protocol. Relative risk (RR) was calculated by using random-effects models and was tested in subgroups of different patient comorbidities, contrast medium types, and AKI diagnostic criteria. RR results of less than 1.00 indicated that there was a higher incidence of these outcomes in the group that did not receive contrast medium (non-contrast medium group). RESULTS Of the 1489 studies originally identified, 13 nonrandomized studies (0.9%) representing 25,950 patients met inclusion criteria. In the group that received contrast medium (contrast medium group), risk of AKI (RR = 0.79; 95% confidence interval [CI]: 0.62, 1.02; P = .07), death (RR = 0.95; 95% CI: 0.55, 1.67; P = .87), and dialysis (RR = 0.88; 95% CI: 0.23, 3.43; P = .85) was similar, compared with the risk of AKI in the non-contrast medium group. This pattern was observed regardless of i.v. contrast medium type, diagnostic criteria for AKI, or whether patients had diabetes mellitus or renal insufficiency. CONCLUSION Controlled contrast medium-induced nephropathy studies demonstrate a similar incidence of AKI, dialysis, and death between the contrast medium group and control group. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12121460/-/DC1.

Contrast-Induced Nephropathy after Intravenous Administration: Fact or Fiction?

Recent prospective clinical investigations in high-risk patients receiving intravenous contrast media for computed tomography (CT) suggest that the incidence and serious negative clinical outcomes are much less common than previously believed. Additional perspectives comparing random variations in serum creatinine in subjects not receiving contrast media show similar fluctuations that would equate to contrast-induced nephrotoxicity (CIN). Putative mechanisms for how CIN could cause death or other serious adverse clinical consequences have not been elucidated.

Magnetic resonance imaging findings in asymptomatic volunteers and symptomatic patients with temporomandibular disorders

Internal derangement has been suggested to be a cause of temporomandibular disorders. This study compared magnetic resonance imaging findings in 82 asymptomatic volunteers and 263 symptomatic patients. Disk displacement was observed in 33% of the asymptomatic volunteers and 84% of the symptomatic patients. The prevalence of trauma, headache, and other joint problems was more common in symptomatic patients. A history of general anesthesia and orthodontic treatment was not increased in the symptomatic population compared with asymptomatic volunteers. This study suggests that disk displacement is more common in symptomatic subjects.

Functional, dynamic, and anatomic MR urography: feasibility and preliminary findings.

RATIONALE AND OBJECTIVES The authors assessed the feasibility of using magnetic resonance (MR) urography to acquire functional, dynamic, and anatomic information in human subjects with normal and hydronephrotic kidneys. MATERIALS AND METHODS In subjects known to have or suspected of having hydronephrosis, split renal filtration fractions were measured with a customized magnetization-prepared, inversion-prepared gradient-recalled echo sequence to determine the T1 of flowing blood in the inferior vena cava and aorta before and after contrast medium administration and in the renal veins and arteries after contrast medium administration. Multiple timed sets of coronal fast spoiled gradient-echo 70 degrees flip-angle images were acquired before and after contrast medium administration to derive MR renograms from changes in the signal intensity of the cortex and medulla. Precontrast T2-weighted images were obtained with a three-dimensional fast spoiled gradient-echo maximum intensity projection pulse sequence, and postcontrast T1 maximum intensity projection images were also obtained to depict the renal anatomy. RESULTS Split filtration fraction differentiated normal from hydronephrotic kidneys. MR renograms depicted vascular, tubular, and ductal phases and differentiated between normal and hydronephrotic kidneys (P < .05, n = 20). Contrast medium dose correlated with the peak of the cortical signal intensity curves on the renogram (r = 0.7, P < .0005; n = 20). The sensitivities for the visual determination of hydronephrosis and unilateral delayed excretion of contrast material were both 100%, and the specificities were 64% and 85%, respectively. CONCLUSION The preliminary findings show promise for the use of MR urography in the comprehensive assessment of renal function, dynamics, and anatomy.

Condyle position as a predictor of temporomandibular joint internal derangement

STATEMENT OF PROBLEM The significance of the position of the mandibular condyle in the glenoid fossa remains a controversial subject. PURPOSE This study evaluated the relationship between condyle position and disk displacement. MATERIAL AND METHODS Fifty-two asymptomatic volunteers and 130 symptomatic patients underwent linear tomography and bilateral temporomandibular joint magnetic resonance scans. RESULTS There was a higher prevalence of distal condyles in symptomatic patients with disk displacement compared with asymptomatic volunteers (P <.05). Distally positioned condyles identified joints with disk displacement with reduction, disk displacement without reduction, or a symptomatic normal joint with a sensitivity of 0.64, 0.56, and 0.33, respectively. Distally positioned condyles identified joints with disk displacement with reduction, disk displacement without reduction, or a symptomatic normal joint with a specificity of 0.56, 0.65, and 0.55, respectively. CONCLUSION There were more distal condyles in symptomatic subjects with disk displacement, but the reliability of a distal condyle to predict the presence or absence of disk displacement was low.

GADOLINIUM-DTPA TRANSPLACENTAL TRANSFER AND DISTRIBUTION IN FETAL TISSUE IN RABBITS

&NA; Novak Z, Thurmond AS, Ross PL, Jones MK, Thornburg KL, Katzberg RW. Gadolinium‐DTPA transplacental transfer and distribution in fetal tissue in rabbits. Invest Radiol 1993;28: 828‐830. rationale and objectives. The authors assessed to what extent the commonly used the magnetic resonance imaging contrast agent, gadopentetate dimeglumine, crosses the placenta. methods. Eight pregnant rabbits in the third trimester were injected with 0.1 mmol/kg of gadopentetate dimeglumine, and killed 5, 15, 30, or 60 minutes after injection. Placental and fetal tissues were analyzed for gadolinium content. results. Placental concentrations of gadolinium were initially high (16.6 ± 3.4 micrograms/gram) and then declined with a biexponential pattern. Initial gadolinium levels in the fetal organs were low and remained so except for the fetal kidneys, which showed increased levels of gadolinium from 4.3 ± 1.1 micrograms/gram at 5 minutes to 6.8 ± 1.8 micrograms/gram at 60 minutes. conclusions. The results indicate that gadolinium does cross the rabbit placenta, and that concentrations in the placenta and the fetal urinary tract are sufficient for imaging as well as possible fetal toxicity.

Transplacental passage of iohexol

We describe the appearance of an iodinated, low molecular weight radiographic contrast agent, iohexol, in the intestines of twin neonates after administration to a pregnant mother during angiography. Nonionic contrast agents cross the human placenta and enter the fetus in significant concentrations and in this case facilitated identification of an omphalomesenteric duct cyst in one twin.

Indirect computed tomography lymphography using iodinated nanoparticles to detect cancerous lymph nodes in a cutaneous melanoma model

RATIONALE AND OBJECTIVES To evaluate differences in contrast uptake in normal and cancerous lymph nodes on indirect computed tomography (CT) in swine, we conducted lymphographic examinations after subcutaneous injection of a lymphotropic iodinated nanoparticle suspension. METHODS Perilesional subcutaneous contrast injections (2 ml per lesion) of a 15% wt/vol iodinated nanoparticle suspension were made in immature Sinclair miniature swine (n = 5) with cutaneous melanomas. Average attenuation, iodine concentration, node volume, and total iodine uptake were estimated on the CT scans for each opacified lymph node 24 hr after injection. Nodes were classified as normal or cancerous microscopically, and the percentage of tumor replacement was estimated in cancerous nodes. RESULTS Average attenuation and iodine concentration were higher in normal nodes, and total iodine uptake was higher in cancerous nodes with greater than 25% replacement (p < .05). Architectural alterations in opacified cancerous nodes included medullary filling defects, expansile cortical lesions, and disruption of corticomedullary junctions. CONCLUSION Quantitative and qualitative differences in iodinated nanoparticle enhancement characteristics are useful in distinguishing between normal and cancerous lymph nodes on indirect CT lymphography examinations.

A molecular receptor-binding contrast agent for magnetic resonance imaging of the liver.

RATIONALE AND OBJECTIVES A gadolinium complex of polydiethylenetriamine pentaacetic acid polyneogalactosyl polylysine (Gd-DTPA-gal-PL) was developed and tested as a paramagnetic contrast agent for magnetic resonance (MR) imaging of the liver. The agent was designed for receptor-mediated uptake by the asialoglycoprotein receptor (ASGP-R), which is unique to hepatocytes and exhibits high specificity for galactose-terminated glycoconjugates. METHODS Polylysine was alkylated with a mixed anhydride of diethylenetriamine pentaacetic acid. This product was complexed with gadolinium and N-alkylated with 3-oxopropyl-1-thio-beta-D-galactopyranoside. With this reaction sequence, we prepared a gadolinium complex consisting of 2284 galactose groups and 858 chelators per polylysine having 2136 amino groups. Hepatic enhancement was tested by MR imaging of nine rats with liver-implanted mammary adenocarcinoma before and after injection of 20 x 10(-9) mol/kg Gd-DTPA858-gal2284-PL2136. The conjugate was labeled with technetium-99m and tested (1.5 x 10(-10) mol/kg) for hepatic specificity via nuclear imaging. RESULTS Mean hepatic enhancement was 86% within 10 min and remained constant for 25 min. Hepatic relative intensity exceeded preinjection intensities by at least four times the standard deviation of the preinjection values (p < .01). The tumors, which are devoid of ASGP-R, did not exhibit significant enhancement (p > .1). The liver accumulated 90% of the technetium-99m-labeled conjugate. CONCLUSION A molecular paramagnetic ligand to the asialoglycoprotein receptor has been developed for hepatocyte-specific MR contrast enhancement.