Sensitivity of Gd-DTPA-enhanced MR imaging of benign extraaxial tumors

The effect of gadolinium diethylenetriaminepentaacetic acid (DTPA) on the sensitivity of cranial magnetic resonance (MR) imaging was measured in a prospective blinded study. Twenty-two consecutive patients with benign extraaxial tumors underwent MR imaging on a 1.5-T system without and with intravenous administration of Gd-DTPA. Readers independently interpreted the unenhanced and enhanced images without clinical information. The interpretations were compared with the anatomically verified diagnoses. Gd-DTPA improved the sensitivity of MR imaging for benign extraaxial tumors, especially in cases of residual or recurrent acoustic neuromas, multiple tumors (e.g., neurofibromatosis), or inconclusive unenhanced MR images. Enhancement with Gd-DTPA impaired the identification of a skull base tumor.     

Cervical neural foramina: correlative anatomic and MR imaging study

Accurate diagnosis of diseases affecting the cervical neural foramina with magnetic resonance (MR) imaging requires an appreciation of the normal anatomic appearance of the foramen. The MR appearance of the foramen was studied in cadavers and healthy volunteers and was correlated with cadaver cryomicrotome sections. With gradient-echo techniques, foraminal soft tissues are highlighted relative to adjacent bone, making gradient-echo images valuable for evaluating the overall size and contents of the neural foramina. Intravenously administered gadolinium DTPA produces enhancement of all foraminal soft tissues, including the dorsal root ganglion. The nerve roots do not enhance with Gd-DTPA. Gradient-echo pulse sequences and intravenous use of Gd-DTPA represent promising techniques for the evaluation of the cervical foramina.     

Malignant melanoma of the vulva: clinicopathological features

Abstract. From the files of the Scottish Melanoma Group, we have identified 41 cases of vulval malignant melanoma, which represents 1.7% of all the melanomas occurring in women in Scotland, during the period 1979–1989. Thirty-seven were aged 50 years or older with the mean age being 70 years. The average Breslow depth of the lesions was 6.0 mm, with 29 being greater than 3.0 mm in depth. Nineteen cases were polypoidal and 37 were ulcerated. Six patients had radical vulvectomy with lymph node dissection, three had biopsy and palliative treatment, and the majority of the remaining patients had local excision only, with surgical margins of less than 2 cm. The 5-year survival rate (available for 23 patients) is 21.7%, compared to 72% for cutaneous melanoma in females, in general, in the same population. In this series, the survival rate is poor, as the lesions occurred in elderly women and the melanomas were thick at presentation. Surgical treatment appears to have been rather conservative in those who were dead from their disease at 5 years.     

Patellar tracking abnormalities: clinical experience with kinematic MR imaging in 130 patients

A kinematic magnetic resonance (MR) imaging technique for assessment of malalignment of the patella, involving the acquisition of multiple sequential axial images of the patellofemoral joint during the early increments of passive knee flexion, was used to evaluate 130 patients (235 symptomatic patellofemoral joints) showing clinical evidence of having patellar tracking abnormalities. Twenty-three of the patellofemoral joints had undergone previous surgical procedures for patellar realignment. In addition, 14 (28 patellofemoral joints) asymptomatic control subjects were studied. Normal patellar tracking was observed in all of the asymptomatic subjects and in 43 (17%) of the 260 patellofemoral joints in the patient population, 18 (7%) of which were symptomatic. Sixty-nine (26%) of the patellofemoral joints had lateral subluxation of the patella, 106 (41%) had medial subluxation of the patella, 21 (8%) had excessive lateral pressure syndrome, 19 (7%) had lateral-to-medial subluxation of the patella, and two (1%) had dislocation of the patella. Of the 235 patellofemoral joints with suspected abnormalities, 217 (93%) had patellar malalignment. Of the 23 patellofemoral joints that had undergone prior surgery, 20 (87%) had abnormal patellar tracking. Thirteen of 14 (93%) patellofemoral joints that had undergone a prior arthroscopic lateral retinacular release had a medially displaced patella.     

Discoid menisci of the knee: MR imaging appearance

Discoid menisci of the knee are not uncommon, and the criteria for arthrographic diagnosis and the clinical symptoms are well known. Although enlarged menisci have been recognized at magnetic resonance (MR) imaging, there are no criteria for the MR imaging diagnosis. The authors describe 29 discoid menisci imaged by means of MR. A discoid meniscus was said to be present if three or more 5-mm-thick contiguous sagittal images demonstrated continuity of the meniscus between the anterior and posterior horns. High-resolution coronal images allowed more graphic depiction of the abnormally wide meniscus. In approximately one-third of the cases in which coronal images were obtained, the measurable height difference between the discoid and the opposite meniscus was greater than or equal to 2 mm. Arthroscopic correlation (obtained in 10 cases) revealed that six cases of discoid meniscus were diagnosed correctly with MR imaging, although one meniscus was considered discoid at MR imaging but was not considered discoid at arthroscopy. Of three discoid menisci seen to be torn at arthroscopy, two were seen to be torn at MR imaging.     

Blood MR signal suppression by preexcitation with inverting pulses

A cardiac-gated sequence has been developed for functional cardiac imaging. It uses a nonselective 180 degrees preinverting pulse before a spin-echo (SE) readout sequence with an echo time (TE) of 28 msec. In seven healthy volunteers this sequence provided superior wall-to-chamber contrast in end diastole and end systole when compared with the following sequences: SE, TE = 28 msec; SE, TE = 28 msec with dephasing gradients; and SE, TE = 28 msec with presaturation bands.