Short-Ti inversion-recovery pulse sequence: analysis and initial experience in cancer imaging

Inversion recovery (IR), commonly considered a pulse sequence capable of producing T1-weighted images with excellent display of normal anatomy, is versatile: The null point and peak time provide a useful, succinct summary of the properties of IR and its capacity for producing both T1- and T2-weighted images. Shortening of the inversion time (TI) and creation of a short-TI inversion-recovery (STIR) pulse sequence increases sensitivity to malignancy and other abnormalities by making the effects of prolonged T1 and T2 on signal intensity additive and by nulling the signal from fat. The authors examined over 300 patients with various malignancies and compared STIR images with T1- and T2-weighted images obtained at 0.5 T. In 43 cases, signal-difference-to-noise ratios (SD/Ns) were calculated between tumor, fat, and muscle. In general, STIR images demonstrated tumor as a conspicuously high-intensity area in a background of muted, discernible anatomic detail. The good contrast achieved with STIR sequences between tumor and fat (SD/N = 18.1) and tumor and muscle (SD/N = 12.9) consolidated into a single image the information contained separately on T1- and T2-weighted images, which facilitates efficient detection and localization of malignancy.     

Progression of meniscal degenerative changes in college football players: evaluation with MR imaging

Intrameniscal degenerative changes, presumably due to mild repetitive trauma, have been shown in many college and professional athletes, but it is uncertain over what period of time they can develop or significantly progress. To ascertain this period, the authors used magnetic resonance (MR) imaging to examine one knee in each of 20 players in the starting lineup of a major college football team before and after the season. Only asymptomatic knees (right, n = 10; left, n = 10) were examined; the images were reviewed blindly by one experienced observer without reference to the other examination. A significant progression existed in the grade of signal intensity shown in the menisci over the course of the season (P less than .001). Although this is a small study covering only 1 year, these preliminary results suggest that significant degeneration can occur in the menisci of asymptomatic players over a single season.     

Electrocardiographic T‐ and U‐Wave Discordance

Background: Abundant information has been reported regarding the U wave, which almost entirely has been focused on U waves in isolation. There has been little investigation of discordant T and U waves. Methods: Of 18,750 consecutively recorded electrocardiograms, 143 patients were categorized resulting in three groups. Group A: 53 patients with negative T waves and positive U waves (Type I Discordance); Group B: 26 patients with positive T waves and negative U waves (Type II Discordance); and Group C: 63 patients with negative T and negative U waves. Each patient's chart was reviewed for relevant clinical, laboratory, and medical history. Results: Coronary disease was slightly more common in Group A (64%) than in Group B (46%) (P = 0.174; ns). Coronary disease in Group C was extremely common (88%; P <0.001). Hypertension in the two discordant groups was similar: Group A (60%) versus Group B (58%) (P = ns), Group C was significantly higher (88%) (P <0.001). Left ventricular hypertrophy was 49% in Group A and 58% in Group B (P = ns), but Group C was significantly higher at 70% (P = 0.038). Conclusions: This appears to be the first investigation of the associations of discordant T and U waves. We found that the significance of any U wave is not independent of their respective T wave. In addition, we propose that the U wave not be analyzed in isolation, but rather with respect to its T wave.     

MRI of indeterminate adrenal masses

The histologic type of adrenal tumors can be accurately predicted by MRI on the basis of their signal intensity on a T2-weighted image. However, a small but significant number of nonfunctioning adenomas, carcinomas, and metastases cannot be differentiated because they have similar signal intensities on a spin-echo 2500/80 scan. Eight (21%) of 38 of these tumors fell into this group. Differentiation between incidental adenomas and metastases can be conclusively achieved only when the primary neoplasm can also be imaged and displays high signal intensity on T2-weighted images.     

CT evaluation of thickened esophageal walls

A study of 200 consecutive chest computed tomographic (CT) examinations revealed thickened esophageal walls (over 3 mm) in 35%. While this is the earliest finding of carcinoma of the esophagus on CT, only half of the cases of thickened walls were due to esophageal carcinoma. Other mediastinal malignancies as well as benign inflammatory, vascular, and fibrotic conditions such as reflux and monilial esophagitis, esophageal varices, and postirradiation scarring were found to cause thickened esophageal walls. Distension with air and intravenous enhancement aid in the optimal evaluation of the esophagus by CT. The thickened esophageal wall is always abnormal, but it is nonspecific, seen in both malignant and nonmalignant conditions.