Radiology

Heiserman, J E; Drayer, B P; Keller, P J; Fram, E K

doi: N/Apmid: 1438743

To assess the usefulness of magnetic resonance (MR) angiography in the characterization of intracranial arterial stenosis and occlusion, a three-dimensional time-of-flight method was compared with conventional angiography in 214 vessels in 29 patients. Studies were independently interpreted by two neuroradiologists who scored each vessel as normal, narrowed, or occluded. Overall, 97% of normal vessels and 100% of occlusions were correctly graded. Sixty-one percent of stenoses were graded correctly; the remainder were graded as normal. The portions of the intracranial vessels near the skull base and especially the paracavernous and supraclinoid segments of the internal carotid arteries were areas of frequent over- and underestimation of stenosis due to the presence of dephasing artifacts. In patients with stenosis or occlusion, MR angiography also provided information regarding the presence of collateral flow in the circle of Willis. When used in conjunction with MR imaging of the brain and MR angiography of the extracranial carotid arteries, intracranial MR angiography allows a more complete evaluation of the patient with symptoms of cerebral ischemia or infarction.

Yeh, H C; Halton, K P; Shapiro, R S; Rabinowitz, J G; Mitty, H A

doi: N/Apmid: 1438753

The so-called hypertrophic column of Bertin is a normal variation and simply represents unresorbed polar parenchyma of one or both of the two subkidneys that fuse to form a normal kidney. It contains renal cortex, pyramids, and columns (septa) of Bertin. (Since all elements of the tissue are normal, that is, neither hypertrophic nor a displaced or embryonic rest, it is referred to as "junctional parenchyma.") When a masslike lesion is suspected at sonography or excretory urography, diagnosis of junctional parenchyma can be made with a high degree of certainty when sonography shows that the structure (a) is located between the overlapping portion of two renal sinus systems, (b) is bordered by a junctional parenchymal line and defect, (c) contains renal cortex, pyramids, and columns of Bertin, and (d) contains renal cortex that is continuous with the adjacent renal cortex of the same subkidney.

Moulopoulos, L A; Varma, D G; Dimopoulos, M A; Leeds, N E; Kim, E E; Johnston, D A; Alexanian, R; Libshitz, H I

doi: N/Apmid: 1438772

Spinal magnetic resonance (MR) imaging was performed in 29 patients with newly diagnosed, untreated multiple myeloma. Nineteen (66%) patients were asymptomatic. Sagittal pre- and postcontrast T1-weighted spin-echo images and gradient-recalled-echo images of the thoracic and lumbosacral spine were obtained. Marrow involvement was identified in 20 (69%) patients. There were three MR patterns: focal lesions in nine patients (31%), diffuse involvement in seven (24%), and an inhomogeneous pattern of tiny lesions on a background of normal marrow in four (14%). A statistically significant correlation between MR imaging patterns of marrow involvement and serum hemoglobin values (one-way, P = .0899; Kruskal-Wallis, P = .0620) and between MR imaging patterns and percentage of marrow plasmacytosis (Kruskal-Wallis, P = .0314) was noted, with patterns of diffuse and focal marrow involvement associated with more abnormal values. Spinal MR imaging in patients with early myeloma may reveal marrow involvement in both symptomatic and asymptomatic patients. Some correlation was found between MR imaging patterns and laboratory indexes of disease.

Sasson, J P; Dratch, P L; Shortsleeve, M J

doi: N/Apmid: 1438755

The authors report two cases of sulfadiazine-induced obstructive nephropathy that were diagnosed with ultrasound (US). Renal US demonstrated layered clusters of echogenic shadowing material--presumed to be sulfa crystals--which cleared when the crystalluria resolved. The authors conclude that renal US is helpful in diagnosing sulfa calculi and subsequent obstructive nephropathy.

Shellock, F G; Schatz, C J

doi: N/Apmid: 1438747

To determine the existence of tissue heating-associated risks to the eye with magnetic resonance (MR) imaging performed at high specific absorption rates (SARs), corneal temperature was measured in 14 patients immediately before and after MR imaging performed with a 1.5-T, 64-MHz unit and a quadrature-driven body coil for radio-frequency transmission and a receive-only local coil designed for eye imaging. Fast spin-echo pulse sequences were used predominantly. Estimated peak SARs ranged from 3.3 to 8.4 W/kg. A statistically significant (P < .001) increase in average corneal temperature (32.2 degrees C +/- 0.7 before imaging, 33.1 degrees C +/- 0.6 after) was associated with MR imaging of the eye. The changes in corneal temperature ranged from 0.2 degrees to 1.8 degrees C (average, 0.9 degrees C). The highest corneal temperature measured after MR imaging was 35.1 degrees C. MR imaging performed with a dedicated local coil at the SARs studied produced elevations in corneal temperature that were physiologically inconsequential and below the temperature threshold (41 degrees to 55 degrees C) for radio-frequency radiation-induced cataractogenesis.

Morvan, D; Leroy-Willig, A; Jehenson, P; Cuenod, C A; Syrota, A

doi: N/Apmid: 1438778

To investigate temperature increases in tissues during magnetic resonance (MR) imaging or spectroscopy, the authors measured temperature changes in vitro and in vivo (leg of a volunteer) in a condition simulating hydrogen-1 decoupling in MR spectroscopy. Noninvasive measurements were obtained by using the temperature dependence of the translational diffusion coefficient of water. Temperature was measured at 0.5 T (86 MHz) by using a stimulated-echo sequence that included intense gradient pulses and a procedure reducing sensitivity to bulk tissue motion. Calibration curves of the diffusion coefficient against thermocouple-measured temperature were obtained for a gelatin phantom and bovine muscle. Temperature changes were 5.3 degrees C +/- 0.5 at 2.5 cm from the coil in gelatin and 7.7 degrees C +/- 0.5 at 0.7 cm in bovine muscle. The temperature changed by 4.9 degrees C +/- 1.9 at 2.2 cm from the coil in the calf muscle of a volunteer. The H-1 decoupling protocol can be adapted (modifications in transmission power, duty cycle) to reduce heating effects to below safety recommendations.

Hull, J E; Hunter, C S; Luiken, G A

doi: N/Apmid: 1438766

Fifty Groshong catheters were placed in 50 patients with use of ultrasound (US) and fluoroscopic guidance in the radiology suite: 49 were placed via the subclavian vein and one was placed via the left internal jugular vein. All (100%) attempts at catheter placement were successful. Imaging guidance affected the placement of catheters in 12 cases (24%), including four patients (8%) in whom vascular access would not have been possible with blinded percutaneous venipuncture or surgical cutdown. After a four-case learning curve period, during which one pneumothorax (2%) and two arterial punctures (4%) occurred, there were no further venipuncture-related complications. One catheter was removed because of infection (2%) and one because of allergic reaction (2%) to the antimicrobial cuff. Four patients with cutaneous infections and one with catheter-related sepsis were successfully treated with antibiotics. Results demonstrate the initial promise of imaging-guided placement of central venous access catheters when performed in the radiology suite.

Kannus, P A

doi: N/Apmid: 1438776

The position of the patella was studied prospectively in both knees of 45 consecutive patients (21 male and 24 female patients aged 16-48 years who were competitive n = 17 or recreational n = 28 athletes) who had unilateral patellofemoral pain syndrome without symptoms or signs of patellar instability at initial examination. In each knee, standardized anteroposterior, lateral, and tangential radiographs were obtained and six indexes of patellar position (the ratio of the patellar tendon to the greatest diagonal length of the patella, sulcus angles, lateral patellofemoral angle, lateral patellar displacement, patellofemoral index, and knee angle) were measured. When healthy and affected knees were compared, high riding of the patella due to long patellar tendon (patella alta) was the only definite finding in the affected knees. The shape of the intercondylar sulcus and the mediolateral position of the patella were identical in both knees, providing no evidence for patellofemoral incongruence or lateral patellar tilt. Results of this study strongly suggest that idiopathic retropatellar pain is closely associated with patella alta.

Hopper, K D; Abendroth, C S; Sturtz, K W; Matthews, Y L; Shirk, S J

doi: N/Apmid: 1438769

The performances of seven techniques and devices used with 22-gauge needles to obtain biopsy specimens for cytologic analysis were compared by means of single-blinded evaluation with an objective, previously published grading scheme. A total of 420 specimens were obtained from 10 fresh human cadavers (42 specimens per cadaver), including 30 hepatic, 20 renal, and 10 pancreatic specimens per technique or device. No statistical differences existed in the liver, kidney, or pancreas or in the combined data in the performance of the aspirator gun, syringe holders, vacuum needle, and end-cut gun versus the manual aspiration biopsy technique performed with a 22-gauge Chiba needle. However, nonaspiration, fine-needle capillary biopsy (FNCB) performed statistically significantly worse than any other technique or device in the kidney and pancreas and in comparison with the overall combined data. In the liver, no statistically significant difference existed in the overall performance of FNCB versus conventional aspiration biopsy, but the amount of cellular material obtained with FNCB was statistically significantly less.

Balthazar, E J; Birnbaum, B A; Megibow, A J; Gordon, R B; Whelan, C A; Hulnick, D H

doi: N/Apmid: 1438761

In 19 patients with closed-loop intestinal obstruction, including 16 patients with strangulating obstruction, the findings at examination with computed tomography (CT) were retrospectively correlated with the surgical and pathologic findings and evaluated by two radiologists. Signs of closed-loop obstruction, present in 15 patients, were associated with the configuration of the incarcerated loop of small bowel, abnormalities detected at the site of obstruction, or both. These abnormalities were the following: a U-shaped, distended, fluid-filled bowel loop; the whirl sign; the beak sign; a triangular loop; two adjacent collapsed loops of bowel at the site of obstruction; or all of these. CT signs of strangulation, seen in 10 of the 16 patients with ischemic or infarcted bowel, were associated with the appearance of the bowel wall (thickening, high attenuation, and the target sign), abnormalities in the attached mesentery, or both. In mechanical obstruction of the small bowel, detection of ischemic changes in the bowel wall or mesentery with CT indicates strangulation. Absence of CT findings of ischemia or infarction does not rule out strangulation.