Current Applications of MRI-Guided Laser Interstitial Thermal Therapy in the Treatment of Brain Neoplasms and Epilepsy: A Radiologic and Neurosurgical Overview.

Minimally invasive stereotactic tumor ablation is a viable option for the treatment of benign and malignant intracranial lesions. Although surgical excision constitutes first-line therapy for various brain pathologies, it can cause irreversible neurologic deficits. Additionally, many patients who may benefit from surgery do not qualify as surgical candidates due to multiple comorbidities. Recent advancements in laser interstitial thermal therapy, namely the ability to monitor ablation in real-time under MR imaging, have improved the safety and efficacy of the procedure. MRI-guided laser interstitial thermal therapy is currently used as a minimally invasive treatment for brain metastases, radiation necrosis, glioma, and epilepsy. This article will discuss the principles, suggested indications, complications, and imaging characteristics of MRI-guided laser interstitial thermal therapy as they pertain to the treatment of brain pathology.

A comparison between dynamic pelvic magnetic resonance imaging and videoproctography in patients with constipation.

PURPOSE: This study attempts to compare the diagnostic efficacy of dynamic pelvic magnetic resonance imaging with that of videoproctography for the presence of rectocele, sigmoidocele, and intussusception as well as the measurement of anorectal angle and perineal descent in constipated patients. METHODS: Patients volunteering for the study and fulfilling the criteria for videoproctography to evaluate constipation were also scheduled for dynamic pelvic magnetic resonance imaging. Patients undergoing videoproctography were placed in the left lateral decubitus position, after which 50 ml of liquid barium paste was introduced into the rectum. After this, approximately 100 ml of thick barium paste similar to stool in consistency was injected into the rectum, and the patient was instructed to defecate while video images were taken. For dynamic pelvic magnetic resonance imaging, air, to be used as contrast, was allowed to accumulate in the rectum via examination with the patient in the prone position. A capsule was taped to the perineal skin immediately posterior to the anal orifice for marking. Sagittal and axial T1 images were obtained through the pelvis at 8-mm intervals with dynamic breathhold sagittal images of the anorectal region obtained at rest and during strain and squeeze maneuvers. Total acquisition time per maneuver was approximately 19 seconds. The tests were performed by different examiners blinded to the result of the other evaluation. The investigations were independently interpreted, findings compared, and patients questioned regarding their impression of dynamic pelvic magnetic resonance imaging and videoproctography. RESULTS: From June 1996 to April 1997, 22 patients (15 females) with a mean age of 68 (range, 21-85) years underwent both videoproctography and dynamic pelvic magnetic resonance imaging. Dynamic pelvic magnetic resonance imaging was only able to detect 1 of 12 (8.3 percent) anterior rectoceles and one of two (50 percent) posterior rectoceles identified by videoproctography. It failed to recognize any of the rectoanal intussusception (zero of four) but did show 9 of 12 (75 percent) sigmoidoceles. Significant discrepancy of measurement of the anorectal angle and perineal descent exists between the two studies, and dynamic pelvic magnetic resonance imaging was not able to detect any (0 of 11) of the patients with increased fixed perineal descent and only half (one of two) of the patients with increased dynamic perineal descent noted on videoproctography. All 22 patients preferred dynamic pelvic magnetic resonance imaging over videoproctography because of greater comfort. CONCLUSION: Occasionally, the increased cost of new technology can be justified by the enhanced diagnostic yield. The ability to avoid unnecessary surgery or, conversely, to continue to search for otherwise occult pathology that can be surgically corrected justifies routine application of these new tools. However, this study has shown that, despite a cost of approximately ten times more for dynamic pelvic magnetic resonance imaging than for videoproctography, no clinical changes were made. Thus, on the basis of this study, we cannot endorse the routine application of dynamic pelvic magnetic resonance imaging for the evaluation of constipated patients. In certain selected individuals, it may play a role, but further study is necessary to clarify its exact role.

A pilot assessment of whether external coil MRI is useful to assess evacuatory disorders.

This study assessed the value of common surface coil magnetic resonance imaging (MRI) in patients with evacuatory disorders including fecal incontinence and constipation. These findings were then compared with those from other standard physiological examinations and/or surgical findings. From July 1996 to June 1997, 14 consecutive patients underwent surface coil MRI for evaluation of either fecal incontinence (n=5) or constipation (n=9). In patients with incontinence we compared the findings from endoanal ultrasound (EAUS), anal MRI, and surgery regarding morphopathological findings of the internal and external anal sphincter components. In constipated patients the findings of videoprography and dynamic pelvic MRI were compared regarding the presence of rectocele, rectoanal intussusception, and sigmoidocele as well as the measurements of anorectal angle and perineal descent. The five incontinent patients were all women, with a median age of 67 years (range 43-77). EAUS revealed an anterior sphincter defect in two patients, a posterior defect in one, and normal anal sphincter images in two. Surgical findings confirmed an anterior external anal sphincter scar in two patients, an internal anal sphincter defect in one, and an anatomically normal anal sphincter in two. In one patient, although anal MRI showed posterior external anal sphincter defect, EAUS and surgery revealed normal external anal sphincter appearance. The accuracy rate between EAUS and anal MRI was only 20%, that between surgery and anal MRI 40%, and that between surgery and EAUS 80%. Thus EAUS was more accurate than anal MRI in incontinent patients. The nine constipated patients were all women, with a mean age of 59 years (range 40-78). Videoproctography revealed an anterior rectocele in six patients, rectoanal intussusception in three, and sigmoidocele in five; no abnormalities were identified in two patients. On dynamic pelvic MRI anterior rectocele was seen in three patients and sigmoidocele in two, and five studies were interpreted as normal. One of the patients underwent sigmoidectomy for sigmoidocele, and five patients were treated by biofeedback. Thus the accuracy rate of dynamic pelvic MRI against videoproctography was 60% for anterior rectocele, 40% for sigmoidocele, and zero for rectoanal intussusception. In conclusion, neither MRI for the evaluation of patients with fecal incontinence nor for the evaluation of patients with constipation added any significant information that would warrant its continued use in these patient groups. Perhaps the more widespread availability of an endoanal coil will alter this conclusion; however, at the present time we cannot routinely endorse the expense, time, or inconvenience of these MRI investigations in patients with these diagnoses. Larger prospective comparative studies are required prior to endorsing the technique.

Proposed algorithm to aid the diagnosis of cerebellopontine angle tumors.

Hearing and/or balance disorders are symptoms that may be associated with tumors of the cerebellopontine angle (CPA). Between March 1988 and May 1995, 22 patients had diagnosis or evaluation of CPA tumors at Cleveland Clinic Florida. The most common presenting signs or symptoms included unilateral low-frequency tinnitus, unsteadiness, and/or asymmetric hearing loss. On the basis of our experience, we have constructed an algorithm to help identify and manage acoustic nerve dysfunction. We compare our findings with national epidemiologic data and current medical reports.

Asymptomatic annular pancreas: detection by magnetic resonance imaging.

We report the features of annular pancreas on magnetic resonance imaging in an asymptomatic adult. Fat suppressed T1-weighted imaging sequence demonstrated normal appearing pancreatic tissue encircling the duodenum, and depicted an aberrant ventral pancreatic duct.

Natural history of acquired immunodeficiency syndrome in women in Rhode Island.

PURPOSE: Current recommendations for treatment of human immunodeficiency virus (HIV) infection and for prophylaxis against associated opportunistic infections in North America are largely based on observations of HIV infection in males. In an effort to determine whether the natural history and clinical course may be different, with implications relevant to prophylaxis against opportunistic infections, we have documented the clinical courses of the first 24 known cases of acquired immunodeficiency syndrome (AIDS) in women in Rhode Island, most of whom developed Centers for Disease Control-defined AIDS before the availability of an effective antiviral agent (i.e., zidovudine) or a well-defined approach to prophylaxis against opportunistic infections (e.g., oral trimethoprimsulfa). PATIENTS AND METHODS: The subjects in this study are 24 women with AIDS who were treated by members of the Brown University medical faculty from June 1982 through June 1988. All patients had thorough clinical evaluations and appropriate laboratory studies as they became available. All were followed at intervals no greater than two months. All opportunistic infections were treated by appropriate, specific antimicrobial therapy. When zidovudine became available, it was administered to all remaining patients in the study. All subjects were counseled about HIV infection, its modes of transmission, and the early symptoms of opportunistic infections. RESULTS: These observations yielded the following three major findings: (1) Candida esophagitis was the most common (38%) AIDS-defining event; (2) Pneumocystis carinii pneumonia was less frequently the AIDS-defining event (13%) and occurred less commonly during the illness (29%) than in North American males with AIDS; (3) Of 14 women in whom the diagnosis of AIDS was established before January 1, 1987, the mean survival time after diagnosis was greater than 20 months. CONCLUSION: More information on the natural history of HIV infection in North American women is urgently needed. If more extensive data from other geographic regions confirm the observations in this study, the optimal approach to prophylaxis against opportunistic infections in women with AIDS may be substantially different from that which is most appropriate for males.

Primary renal angiosarcoma mimicking a renal cell carcinoma.

Primary renal angiosarcoma is a very rare malignant tumor that closely mimics the more common renal cell adenocarcinoma (hypernephroma) in radiologic appearance. Both tumors are hypervascular masses and the diagnosis must be confirmed histologically. However, in the presence of a tumor with a capsular blood supply, and in the absence of venous invasion, the diagnosis of renal angiosarcoma may be suggested, especially in a patient with a new onset of consumption coagulopathy.

Feminizing adrenocortical tumors in male patients: adenoma versus carcinoma.

We report a case of a feminizing adrenocortical adenoma in a 8-year-old boy and feminizing carcinoma in a 25-year-old man. Because diagnosis of adrenal malignancy in such tumors by histopathological criteria is not always conclusive, a clinicoradiological approach may be used in the evaluation.