MR imaging of the penis.

The signal intensity of the corpora cavernosa of the penis at magnetic resonance (MR) imaging may vary from that of the corpus spongiosum; this difference is dependent on the rate of blood flow within the cavernous spaces that constitute the corporal bodies. Also visible at MR imaging are the layers of fibrous tissue that envelop the corporal bodies, the deep arteries and veins, subcutaneous connective tissue, tunica dartos, epidermis, and urethra. While the iliac, pudendal, perineal, and common penile arteries can be evaluated with three-dimensional MR angiography, the smaller end arteries of the penis have not yet been reliably demonstrated. MR imaging may be used to detect and stage penile and urethral cancers, identify and characterize benign penile masses, evaluate arteriogenic impotence, identify penile fractures, evaluate penile prostheses, localize periurethral abscesses, and identify plaques of Peyronie disease. With its direct multiplanar imaging capabilities, superb soft-tissue contrast, and excellent spatial resolution, high-field surface coil MR imaging can show the soft-tissue and vascular anatomy of the penis, as well as the appearance of many penile diseases.

Distribution of topical medication in the human vagina as imaged by magnetic resonance imaging.

OBJECTIVE: To assess the use of magnetic resonance imaging (MRI) to determine the varying distribution of a vaginally placed gel over time and with different levels of patient activity. DESIGN: Prospectives interventional trial. SETTING: University medical center. PATIENT(S): One nulliparous volunteer with normal menstrual cycles and no gynecologic disease who underwent seven MRI scans of the pelvis. INTERVENTION(S): Five mL of a commercially available topical spermicide was mixed with gadolinium-chelate magnetic resonance contrast material and introduced with a standard applicator. T1-weighted three-dimensional MRI was done to assess the distribution of the gel. MAIN OUTCOME MEASURE(S): Gel thickness and distribution. RESULT(S): The initial bolus of gel was delivered into the upper portion of the vagina, above the urogenital diaphragm. Thereafter, it spread into the vaginal fornices and "flattened" to cover the lateral aspects of the vagina. Without ambulation, the majority of spread was confined to the upper vagina. With ambulation and longer elapsed time, the gel spread further in the upper vagina and into the lower vagina, and significant vaginal surface coverage increased significantly. CONCLUSION(S): Magnetic resonance imaging can be used to monitor the spread of vaginally placed products and to evaluate coverage of topical drugs used for prevention and treatment, including those used for HIV prophylaxis.

Distribution of a spermicide containing Nonoxynol-9 in the vaginal canal and the upper female reproductive tract.

Topical, intravaginal microbicides and spermicides are greatly needed to prevent transmission of sexually transmitted diseases and/or unwanted pregnancies. The development of such compounds is a high research priority. The presumed method of action of existing, or novel, microbicides/spermicides is to provide a chemical barrier to the vaginal epithelium preventing exposure to micro-organisms. Other intravaginal products are used to treat vaginal bacteria of fungal infections. Little is known, however, about the actual or optimal initial distribution and subsequent spread of medications placed in the vagina. We describe a sensitive new technique to quantify the spread of a gel placed in the vagina using magnetic resonance imaging (MRI). Five millilitres of an over-the-counter spermicide containing Nonoxynol-9 was mixed with Gadolinium. MRI was used to quantify spread of the mixture 10 min after insertion with a standard applicator. We demonstrated contiguous spread of gel throughout the vagina. The coverage of material was thicker in the upper vagina than in the lower vagina. We also demonstrated, for the first time, that spermicidal compounds may migrate from the vaginal canal into the endocervix within 10 min of insertion. This finding suggests that topical microbicides/spermicides may act both in the vaginal canal and in the upper female genital tract.

Magnetic resonance imaging of the ovary.

Magnetic resonance imaging (MRI) of the pelvis can characterize a wide variety of ovarian lesions. We discuss MRI strategies for identification and characterization of ovarian neoplasms and correlate MRI findings with lesion gross pathological and histopathological structure.

Helical CT of skeletal muscle metastases from primary carcinomas.

OBJECTIVE: To determine the clinical and helical CT findings in patients with skeletal muscle metastases from carcinoma, we reviewed the cases of 15 consecutive patients who had muscle metastases diagnosed by contrast-enhanced helical CT. MATERIALS AND METHODS: Between February 1992 and August 1997, 15 patients (30 lesions) had metastatic disease to muscle from primary carcinoma diagnosed by helical CT in our institution. Patient data and imaging findings were retrospectively reviewed. RESULTS: Ten of 15 patients (67%) were known to have a malignancy at the time of CT. Patients complained of pain at the site of skeletal muscle metastases in five (17%) of 30 lesions, and in 11 (37%) of 30 lesions a mass was palpable. Lesion size averaged 3.2 cm (range, 0.7-7.8 cm). Thirteen of 15 patients had metastatic disease elsewhere at the time of skeletal muscle metastasis diagnosis. Muscles and other structures most commonly involved by metastatic disease included erector spinae (n = 9), psoas (n = 4), rotator cuff (n = 4), gluteal (n = 3), and abdominal (n = 3). The most common appearance of metastatic disease to muscle on contrast-enhanced helical CT was that of a rim-enhancing mass with central hypoattenuation in 25 (83%) of 30 lesions. CONCLUSION: Metastatic disease to skeletal muscle tends to be found in people with advanced-stage neoplasms. It may be an incidental finding on CT because pain is an uncommon feature; a minority of lesions were palpable in our series. The most common appearance on contrast-enhanced helical CT is a rim-enhancing intramuscular lesion with central hypoattenuation.

MR imaging of renal neoplasms.

MR imaging has many advantages over other modalities in the detection and staging of renal neoplasms, because of its intrinsic high soft tissue contrast, direct multiplanar imaging capabilities, and the availability of a non-nephrotoxic, renally excreted contrast agent. The ongoing refinement of breath-hold imaging sequences will probably broaden the use of MR techniques in imaging renal neoplasms.

Volume-rendered three-dimensional spiral CT: musculoskeletal applications.

Spiral computed tomography (CT) is a powerful modality for evaluation of the musculoskeletal system, particularly when coupled with real-time, volume-rendering reconstruction techniques. Including volume-rendered spiral CT in routine musculoskeletal imaging protocols can change management in a significant number of cases. In cases of trauma, subtle fractures--particularly those oriented in the axial plane--are better seen on volume-rendered images. Complex injuries can be better demonstrated with volume-rendered images, and complicated spatial information about the relative positions of fracture fragments can be easily demonstrated to the orthopedic surgeons. The use of intravenously administered contrast material allows simultaneous evaluation of osseous and vascular structures within the affected area. Evaluation of suspected infectious or neoplastic disease is also aided by including volume-rendered imaging in the musculoskeletal spiral CT examination. The extent of disease can be thoroughly evaluated with volume-rendered images, and therapeutic planning--be it surgical or medical--is aided by the anatomic information available from volume-rendered images. Postoperative studies in patients with orthopedic hardware also benefit from volume-rendered imaging. Volume rendering eliminates most streak artifact and produces high-quality images on which the relationships among hardware, bones, and bone fragments are well demonstrated.

Spiral CT and three-dimensional CT of musculoskeletal pathology. Emergency room applications.

Spiral CT is a fast and effective modality for evaluating a wide variety of musculoskeletal abnormalities in the emergency department setting. The role of spiral CT in evaluating musculoskeletal trauma and musculoskeletal inflammation and infections is discussed, as is the use of multiplanar and three-dimensional imaging.

Renal neoplasms amenable to partial nephrectomy: MR imaging.

PURPOSE: To determine the magnetic resonance (MR) imaging characteristics of renal lesions in patients who undergo technically successful partial nephrectomy. MATERIALS AND METHODS: Between February 1991 and September 1997, 38 patients (41 lesions) who underwent partial nephrectomy at a single institution were preoperatively evaluated with contrast material-enhanced, multiplanar, surface-coil MR imaging. Imaging findings that could affect the decision to perform partial nephrectomy were retrospectively evaluated: tumor size; tumor location; presence of pseudocapsule; suspected tumor invasion of renal sinus fat, renal collecting system, renal vein, or perinephric fat; and morphologic and physiologic status of the contralateral kidney. Correlation was made with surgical and pathologic findings. RESULTS: Thirty-three of 41 lesions (80%) were renal cell carcinomas, five were oncocytic neoplasms (12%), two were hemorrhagic cysts (5%), and one was an angiomyolipoma (2%). Twenty-four of 41 (59%) lesions had pseudocapsules. In most cases, the perinephric fat (n = 38 [93%]), the renal sinus fat (n = 31 [76%]), and the renal collecting system (n = 39 [95%]) were correctly interpreted as being uninvolved by tumor. CONCLUSION: Renal neoplasms amenable to partial nephrectomy can be identified and characterized with contrast-enhanced, multiplanar, surface-coil MR imaging.

Spiral CT with 3D reconstruction in children requiring reoperation for failure of chest wall growth after pectus excavatum surgery. Preliminary observations.

Pectus excavatum is the most common congenital chest wall deformity. Extensive corrective surgery prior to age 3 may disturb chest wall growth and result in a constricted thorax. We describe our surgical and radiologic experience with eight such cases, paying particular attention to the role of spiral computed tomography (CT) with 3D reconstruction in patient management. Spiral CT was performed on children who had developed restrictive chest walls following pectus excavatum surgery. These children then underwent a unique operation to elevate the sternum and attempt to correct their restrictive chest wall defects. In several cases, postoperative spiral CT was performed. Spiral CT with 3D reconstruction defined the orientation of the ribs and costal cartilages and their relationship to the sternum, allowing exact preoperative measurement of the bony rib cage and guiding individualized operative correction. Computed thoracic volumes in select cases correlated well with subjective patient reports of increased exercise capacity. Repair of pectus excavatum defects prior to age 3 may result in constrictive thoracic abnormalities. Surgical correction can increase thoracic volume and improve prospects for normal thoracic function. Three-dimensional reconstruction of spiral CT data is useful in both preoperative and postoperative evaluation.

CT of hemorrhagic complications of anticoagulant therapy.

Anticoagulant therapy is commonly used in patients at risk for, or known to have, thromboembolic disease. Although complications of therapy are uncommon in most patients, in others it may result in complications with substantial morbidity and occasionally may be life threatening. This essay reviews the role of anticoagulant therapy and defines the potential complications that may occur in the chest, abdomen, musculoskeletal system, and CNS. Specific pitfalls in diagnosis as well as complications of the bleeding process are discussed and illustrated. The role of CT scanning in the diagnosis and triage of these patients is clearly defined through select cases and clinical dilemmas.

MR imaging of the wrist.

The use of MR imaging in the area of the wrist has lagged due to the technical challenges posed by the small size of the structures of the wrist. After a careful history, physical examination, and plain films, MR imaging is a powerful next imaging study for solving diagnostic problems involving this complex region. The increasing ability of MR imaging to diagnose wrist abnormalities noninvasively has led to a decrease in the use of invasive techniques.

Tropical pyomyositis: imaging findings and a review of the literature.

Tropical pyomyositis is a rare cause of multiple abscesses of skeletal muscle. The entity is rare in temperate climates and, as its name suggests, is more common in areas such as the tropics and South Pacific. Staphylococcus aureus is the most common cause of infection. Therapy is aggressive, with surgical debridement and drainage followed by antibiotics. We report an unusual case of tropical myositis which simulated tumor recurrence in a patient without the typical risk factors associated with tropical pyomyositis.

Inflammatory pseudotumor of the terminal ileum mimicking malignancy in a patient with Behçet's disease. CT and pathological findings.

Behçet's disease is an idiopathic, recurrent multisystem syndrome characterized by oral aphthous ulcers, genital ulcers, and ocular inflammation. Small bowel involvement may occur in 1% of patients with aphthous ulceration which may mimic Crohn's disease. We report a case of a patient with Behçet's disease with small bowel pathology which simulated a mass and at surgery was an inflammatory pseudotumor. Inflammatory pseudotumors can be mistaken for a malignancy as was the case in this patient.

Helical (spiral) CT of the musculoskeletal system.

Helical (spiral) CT scanning of the musculoskeletal system is a valuable adjunct in patients with complex disease processes where standard radiography may prove to be of limited use. When CT scans are ordered, the use of helical (spiral) acquisition provides specific advantages in terms of ease of performance of the study, potential successful completion of the study, and in quality of the CT data set. Future advances in technology will enhance these advantages.