Safe determination of susceptibility of Mycobacterium tuberculosis to antimycobacterial agents by flow cytometry.

We showed previously that susceptibility testing for Mycobacterium tuberculosis labeled with fluorescein diacetate could be accomplished rapidly by using flow cytometry. However, safety was a major concern because mycobacteria were not killed prior to flow cytometric analysis. In this study, we developed a biologically safe flow cytometric susceptibility test that depends on detection and enumeration of actively growing M. tuberculosis organisms in drug-free and antimycobacterial agent-containing medium. The susceptibilities of 17 clinical isolates of M. tuberculosis to ethambutol, isoniazid, and rifampin were tested by the agar proportion and flow cytometric methods. Subsequently, all flow cytometric susceptibility test samples were inactivated by exposure to paraformaldehyde before analysis with a flow cytometer. Agreement between the results from the two methods was 98%. In addition, the flow cytometric results were available 72 h after the initiation of testing. The flow cytometric susceptibility assay is safe, simple to perform, and more rapid than conventional test methods, such as the BACTEC system and the proportion method.

Flow cytometric testing of susceptibilities of Mycobacterium tuberculosis isolates to ethambutol, isoniazid, and rifampin in 24 hours.

Susceptibility testing of Mycobacterium tuberculosis is seriously limited by the time required to obtain results. We show that susceptibility testing of clinical isolates of M. tuberculosis can be accomplished rapidly with acceptable accuracy by using flow cytometry. The susceptibilities of 35 clinical isolates of M. tuberculosis to various concentrations of isoniazid, rifampin, and ethambutol were tested by the agar proportion method and by flow cytometry. Agreement between the results from the two methods was 95, 92, and 83% for isoniazid, ethambutol, and rifampin, respectively. Only 11 discrepancies were detected among 155 total tests. The results of flow cytometric susceptibility tests were available within 24 h of inoculation of drug-containing medium, while the proportion method required 3 weeks to complete. The flow cytometric method is also simple to perform.

Percutaneous dilation of benign biliary strictures.

Percutaneous balloon dilation of benign biliary strictures was successful in 15 of 18 patients in whom the procedure was attempted. Successful dilation was achieved in nine of 11 patients who had biliary enteric strictures, with follow-up of 22-55 months (mean, 35.4 months) after catheter removal in seven patients. Five of six strictures in the biliary tree that developed after surgery were successfully dilated, with long-term follow-up available in two patients (58 and 42 months). A patient with an inflammatory common bile duct stricture that was successfully dilated was followed up for 18 months. Percutaneous dilation of biliary tract strictures is a promising technique with good long-term results and may be the initial treatment of choice in biliary stricture management.

Percutaneous balloon dilatation of ureteral strictures.

Percutaneous balloon dilatation of ureteral strictures has not gained widespread acceptance, despite proven success with the techniques for dilating stenotic blood vessels. Thirty-one ureteral strictures (in 30 patients) that were dilated during a 42-month period were reviewed to assess the results and to determine which patients are most likely to benefit from the procedure. Eighteen (58%) of 31 strictures were successfully dilated and remained patent for at least 6 months. Thirteen (42%) of 31 strictures resulted in failed patency either immediately (two patients) or within 3 months (seven patients), 6 months (three patients), or 21 months (one patient). Fourteen (64%) of 22 strictures less than 7 months of age were successfully dilated. All dilations for strictures more than 7 months of age failed. Four strictures were of unknown age. Nine (69%) of 13 strictures located in the proximal or midureter remained patent, and three (60%) of five dilations at a ureteroileal anastomosis were successful. Neither of two strictures at a ureterocolic anastomosis was treated successfully. We conclude that percutaneous balloon dilatation is an effective treatment of ureteral strictures in some patients, especially when the strictures are less than 7 months of age.

Nitrous oxide: effective analgesic for vascular and interventional procedures.

During a 2 year period nitrous oxide was used as a sole or supplementary analgesic during 173 vascular or interventional procedures including peripheral angiography and endourologic and endobiliary procedures. The decision to administer nitrous oxide to a given patient was a matter of physician preference. Patients with bowel obstruction, pneumothorax, or chronic obstructive pulmonary disease were excluded from this method of analgesia. The nitrous oxide was administered by a radiology nurse under the supervision of an attending radiologist. Nitrous oxide was used without premedication for 39 procedures and with premedication (usually meperidine 1 mg/kg, promethazine 0.3 mg/kg, or atropine 0.01 mg/kg) in 134 procedures. In 74% of nonpremedicated individuals analgesia was adequate with nitrous oxide alone; 26% required supplemental intravenous medication. In 61% of premedicated individuals pain relief was adequate with nitrous oxide; 39% required supplemental intravenous medication. Complications, including nausea, vomiting, and agitation, occurred in eight patients, but were minor and easily reversed by decreasing the concentration of nitrous oxide. Nasally administered nitrous oxide is a safe, easily used, and effective analgesic.

Percutaneous transluminal angioplasty vs. surgery for renovascular hypertension.

Therapeutic results in 102 hypertensive patients were evaluated after either renal artery percutaneous transluminal angioplasty (PTA) or surgical bypass procedures for renovascular hypertension. A minimum of 6 months of follow-up was accepted to evaluate therapeutic success or failure. Renal angioplasty had a beneficial result in each of 13 patients with fibromuscular dysplasia and in 10 (83%) of 12 patients with atherosclerotic lesions that did not involve the origin of the renal artery. Although surgery was also beneficial in each of six patients with fibromuscular dysplasia, it helped only five of 10 patients with atherosclerosis of the renal artery. Angioplasty results were similar to surgical results for atherosclerotic lesions that involved the origin of the renal artery. Angioplasty was unsuccessful in two cases of neurofibromatosis because of the firm nature of the lesions, where a bypass procedure was successful in one case. Major complications were more common in surgical cases than in angioplasty. PTA is recommended for all renal artery lesions; surgery should be reserved for failed PTA or recurrent renal artery stenosis after PTA.

Percutaneous approach to nephrolithiasis.

Percutaneous techniques were successful in removing stones from 101 (92%) of 110 kidneys attempted. Ultrasonic lithotripsy was used on 80 kidneys in 74 patients with stones 5-38 mm in diameter. The most common complication was incomplete disintegration with retained stone fragments. Twenty patients were treated by direct stone extraction, either by a stone basket or forceps. The average hospitalization for percutaneous stone removal of 10 days was not significantly different from that for open nephrolithotomy. However, patients undergoing percutaneous stone removal had only a 3-10 day convalescence after hospital discharge before returning to normal activity.

Current concepts in computerized tomography of the mediastinum.

Computed tomography (CT) has dramatically changed the imaging approach to the mediastinum. CT can depict precise cross-sectional mediastinal anatomic detail defining fat, water, and near muscle density tissues. Not only diagnosis but staging of some disease processes is now possible. The key to understanding the mediastinum is a sound knowledge of normal mediastinal anatomy and the potential disease processes which may affect the mediastinum. Normal CT mediastinal anatomy is illustrated and discussed. Pathological processes involving the thymus, lymphatics, endocrine systems, and great vessels are emphasized describing their clinical presentations, appearance, and the techniques of examination.

Technique to facilitate percutaneous nephrostomy in non-obstructed kidneys.

A technique for performing antegrade pyelography during nephrotomy is described--puncture with a 21-gauge, 20-cm Cope needle, placement of a 0.018-inch SMG mandril "coat-hanger"-shaped guidewire, with the needle exchanged for a 3-French multi-sidehole dilator. Use of the 3-French dilator provides more security and less trauma to the renal pelvis; nephrotomy time is also curtailed. In 25 patients the technique was used successfully with 2 minor complications.

Computed tomography of benign angiomatous lesions of the extremities.

Thirteen patients with benign angiomatous lesions of the extremities were evaluated by CT. The relationship of the lesion to specific muscle groups and fascial planes was defined better by CT than on plain radiography or angiography. Computed tomography without contrast enhancement demonstrated well circumscribed masses of lower attenuation value than the surrounding muscle. Eight of the 11 patients who received intravenous injection of contrast material showed characteristic punctate or curvilinear structures within the mass, which had attenuation values similar to normal blood vessels. The characteristic CT features of benign angiomatous lesions of the extremities are presented.

CT diagnosis of ruptured abdominal aortic aneurysm.

Abdominal computed tomography was performed in six patients with suspected ruptured abdominal aortic aneurysm but in whom an alternate clinical diagnosis was seriously considered. In each patient, a large aortic aneurysm was demonstrated in association with a retroperitoneal accumulation of high-density blood. The retroperitoneal blood was primarily confined to the extracapsular perinephric space. In four of the six patients, a focal area of the aortic wall was indistinct on the side of the retroperitoneal hemorrhage at the presumed site of rupture. Five of the six patients underwent emergency surgery, which confirmed the site of aneurysm, presence of rupture, and the location of fresh retroperitoneal blood.

CT differentiation of thoracic aortic aneurysms from pulmonary masses adjacent to the mediastinum.

Paramediastinal masses adjacent to the aorta require a diagnostic evaluation to differentiate between tumor and aneurysm. It has been suggested that neoplasm may enhance sufficiently to be confused with a vascular structure or that a clot filled aneurysm may simulate a neoplasm by not filling with contrast medium. Five patients, two with thoracic aneurysms, two with malignancy, and one with a malignancy and an aortic dissection, are presented in whom bolus injection computed tomography (CT) was able to distinguish between aneurysm and mass. The CT examination also accurately visualized the point of communication of the aneurysm with the aorta, defined the relationship of the aneurysm to vital mediastinal structures for planning surgical resection, and helped plan the approach for percutaneous transthoracic needle aspiration when tumor was suspected. Bolus injection CT represents a rational alternative to aortography for mediastinal paraaortic masses.

Computed tomography in the evaluation of thyroid disease.

Traditionally, thyroid imaging has been performed primarily using radionuclide scanning. High-resolution computed tomography (CT) was performed in 18 patients to evaluate the CT appearance of various thyroid abnormalities including diffuse toxic goiter, multinodular goiter, Hashimoto thyroiditis, thyroid adenoma, and malignant thyroid tumors. CT images of the thyroid were correlated with radionuclide scanning, surgical findings, and clinical and laboratory results. CT provided a complementary method for evaluation of the thyroid by defining the morphology of the thyroid gland and more precisely defining the anatomic extent of thyroid abnormalities in relation to the normal structures of the neck and mediastinum.

Percutaneous dissolution of renal calculi using ultrasonic litholapaxy.

The surgical treatment of renal calculi has been markedly changed by percutaneous manipulation and ultrasonic dissolution. The low morbidity and decreased cost of this procedure make it an obvious choice over classic surgical operations. We report our experience with percutaneous ultrasonic stone dissolution in 23 patients.

Percutaneous transluminal angioplasty in diabetic patients: an effective treatment modality.

Percutaneous transluminal angioplasty (PTA) was performed for nonhealing ulcers, severe claudication, or rest pain in 10 patients with diabetes mellitus. Twenty-two atherosclerotic lesions were dilated in 15 extremities, including 16 iliofemoral arteries and 6 superficial femoral arteries. The procedure was technically successful in all patients and 8 of 9 (89%) with clinical follow-up showed improvement clinically after the procedure. Diabetes is not a contraindication to PTA; rather this modality can be used effectively to control and treat peripheral vascular insufficiency in diabetic patients.

Closed-system venography in the evaluation of angiodysplastic lesions of the extremities.

Closed-system venography is a minimally invasive, well tolerated method for diagnosing and delineating extremity angiodysplastic lesions. This method involves passive filling of the vascular tree after compressive exsanguination of an extremity and extrinsic occlusion of its arterial supply and venous drainage, thereby creating a static, closed system. Closed-system venography was done in 17 patients, where it correctly identified 11 of 12 surgically confirmed vascular abnormalities. There were no false-positive examinations. Whereas ateriography remains the examination of choice in studying arteriovenous malformations, closed-system venography has demonstrated a superior ability to diagnose and define lesions of capillary and venous origin.

CT detection of iatrogenic percutaneous splenic injury.

Although the potential for splenic injury during left sided thoracentesis or percutaneous renal biopsy is well known, its occurrence has been rarely reported. In a 1 year period we used computed tomography to detect acute splenic, perisplenic, and intraperitoneal hemorrhage in three patients after percutaneous diagnostic and therapeutic procedures in the lower chest and upper abdomen. One patient was asymptomatic, the second developed left upper quadrant pain, and the third required emergency splenectomy.