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Biomedical subjects

M J Sharafuddin

Publications and source records attributed to M J Sharafuddin.

At least 19 recordsLinked to original sources
PubMed1997

Transvenous closure of secundum atrial septal defects: preliminary results with a new self-expanding nitinol prosthesis in a swine model.

BACKGROUND: Our purpose was to evaluate a new prosthesis for percutaneous closure of secundum atrial septal defects (ASDs). METHODS AND RESULTS: Percutaneous closure of surgically created fossa ovalis ASD was attempted in 15 minipigs. The mean balloon-stretched ASD diameter was 12.3+/-2.3 mm (range, 10 to 16 mm). The self-expanding prosthesis was braided from 0.005-in Nitinol wires in the shape of two flat buttons with a short connecting waist with a diameter corresponding to that of the defect to be closed. Polyester filling was added to enhance thrombogenicity. Pulmonary arteriography with levo-phase was obtained before placement; immediately after placement; and at 1-week, 1-month, and 3-month follow-ups. Four animals were killed at 1 week, 1 month, and 3 months for histopathological correlation. Three deaths resulted from ventricular fibrillation (one during anesthesia and two during the placement procedure). Successful placement of the prosthesis was achieved in the remaining 12 animals. Overall immediate ASD closure on angiography occurred in 7 of 12 animals (all polyester-filled prostheses). Absent or trace shunt by angiography was present in 11 of 12 devices at 1 week, with the remaining one demonstrating a small shunt. All septal defects were completely closed at 1 month with the exception of one case in which delayed partial dislodgment of an undersized prosthesis into the right atrium had developed. Closure rate at 3 months was 100%. Neoendothelialization and fibrous incorporation of the prosthesis were completed within 1 to 3 months. CONCLUSIONS: Effective and permanent occlusion of secundum ASDs is feasible with a device that offers the advantages of easy placement, self-centering, and repositionability.

Alloys↗
PubMed1997

Sonographic findings in bone marrow transplant patients with symptomatic hepatic venoocclusive disease.

Sonographic findings were retrospectively compared between 19 patients with hepatic venoocclusive disease and 23 patients with other common causes of symptomatic liver dysfunction after bone marrow transplantation (14 grafts versus host disease and nine hepatitis). Doppler sonographic examination was available in all patients with venoocclusive disease, in nine of the patients with graft versus host disease, and in three of the patients with hepatitis. The hepatic artery resistive index and the overall flow direction, peak forward and retrograde velocities, and time-averaged mean velocities in the hepatic veins and main portal vein were compared. The portal vein waveform was arbitrarily considered abnormal in the presence of any of the following: highly pulsatile waveform, very low mean velocity, biphasic flow, or flow reversal. Ascites was the most predictive gray scale sonographic finding for venoocclusive disease. Doppler sonographic findings of potential value in the diagnosis of hepatic venoocclusive disease include an abnormal portal vein waveform, resistive index of greater than 0.75, and marked thickening and edema of the gallbladder wall. However, the study is limited by its retrospective nature and reliance primarily on clinical criteria for the diagnosis of venoocclusive disease. Therefore, our findings will need to be verified in a large prospective study.

Adult↗
PubMed1995

Sonographic diagnosis of unsuspected gallbladder cancer: imaging findings in comparison with benign gallbladder conditions.

OBJECTIVE: Several sonographic findings were analyzed to determine their significance in distinguishing gallbladder cancer from benign conditions of the gallbladder. The analyzed findings were gallstone number and size; floating stones; displaced stones; wall thickening, irregularity, and echogenicity; mucosal plaque; intraluminal mass; gallbladder-replacing mass; invasive gallbladder mass; gallbladder mucosal discontinuity; hyperechoic gallbladder mucosa; and submucosal or transmural echolucency. MATERIALS AND METHODS: Sonograms of 20 patients with unsuspected, pathologically proven gallbaldder cancer and 65 patients with benign gallbladder conditions (predominantly acute or chronic cholecystitis) were retrospectively assessed by two observers who were unaware of experimental conditions. Gallstone number and size were assessed, and the presence of floating stone (neither settling nor wall-adherent), displaced stone (lifted from the gallbladder wall by mass or focal wall thickening), wall irregularity, mucosal plaque, intracystic mass, and gallbladder-replacing or invasive mass was evaluated. The echogenicity pattern of the gallbladder wall was characterized, and its thickness was measured and classified as normal/mildly thickened (< 7 mm) or moderately/severely thickened (> or = 7 mm). In addition, the gallbladder wall was evaluated for discontinuous mucosal echo, hyperechoic mucosa, submucosal or mural echolucency, and pericholecystic fluid collection. Sonographic findings were compared by the Mann-Whitney test for nonparametric variables and by Student's t test for continuous variables. RESULTS: Solitary gallstone, displaced stone, intraluminal mass, gallbladder-replacing or invasive mass, and discontinuity of the mucosal echo were all statistically significantly more common in patients with gallbladder cancer (.001 < p < .05). Mucosal plaque and wall irregularity were nonspecific findings. Gallbladder wall thickening by itself was nonspecific, although associated echolayering, transmural or submucosal edema, or a distinctly specular mucosal lining favored benign etiologies. CONCLUSION: Several sonographic findings were significantly more common in patients with gallbladder cancer compared with patients with benign gallbladder conditions. Assessment of these signs may be helpful in distinguishing gallbladder cancer from benign conditions of the gallbladder.

Aged↗
PubMed1995

MR imaging of benign soft-tissue masses.

Benign masses outnumber sarcomas. The use of MR imaging for the indeterminate soft-tissue mass has during the past decade permitted radiologists to name the soft-tissue mass or provide a succinct differential diagnosis. This article reviews the identification of benign masses based on signal intensity, location, morphologic characteristics, and other features. The importance of approaching every "indeterminate" mass after MR imaging as malignant until proved otherwise is emphasized, as is the fact that despite the accessibility of the mass, a biopsy should not be done without prior consultation with an orthopedic oncologist.

Biopsy↗
PubMed1995

A comparison of MR sequences for lesions of the parotid gland.

PURPOSE: To compare six MR sequences (plain and gadolinium-enhanced fat suppressed T1-weighted spin echo, T2-weighted standard spin echo, fat-suppressed and non-fat-suppressed T2-weighted fast spin echo, and inversion-recovery T2-weighted fast spin echo) in their ability to detect, delineate, and characterize lesions of the parotid gland. METHODS: Fifty-eight parotid gland lesions imaged on 47 examinations were retrospectively evaluated by three blinded observers. Several outcome-related variables were compared by the above six sequences: imaging time, image quality, anatomic sharpness of parotid space, subjective lesion conspicuity, detected abnormality volume, number of individual lesions or discrete lobulations, conspicuity of invasion into adjacent boundaries and structures, and overall diagnostic value. RESULTS: Differences in the above outcome variables between sequences did not correlate with MR scanner software upgrade level, coil type, or lesion-dependent characteristics. Fat-suppressed fast spin-echo T2-weighted and inversion-recovery fast spin-echo T2-weighted sequences resulted in significantly higher scores for lesion conspicuity, detected abnormality volume, and overall diagnostic value. T1-weighted images resulted in the next highest scores, whereas gadolinium-enhanced T1-weighted and standard spin-echo T2-weighted sequences performed poorly for most parotid lesions. CONCLUSION: MR imaging of the parotid gland should include fat-suppressed, long-repetition-time, fast spin-echo T2-weighted, and T1-weighted sequences. Gadolinium-enhanced images need not be obtained routinely.

Adolescent↗
PubMed1994

MR imaging diagnosis of central precocious puberty: importance of changes in the shape and size of the pituitary gland.

OBJECTIVE: Central precocious puberty occurs as a result of premature pituitary stimulation and increased secretion of gonadotropins. The aims of this study were to analyze MR imaging findings in the pituitary glands of children with central precocious puberty compared with matched control subjects, to define MR imaging-derived variables useful in the diagnosis of central precocious puberty, and to correlate MR imaging-derived variables with the hormonal profile and other imaging and clinical findings. MATERIALS AND METHODS: Twenty-six children with central precocious puberty (two boys and 24 girls) were divided into two subgroups according to MR imaging findings: idiopathic (21 patients) and nonidiopathic (five patients: three hypothalamic hamartomas, one pineal tumor, one empty sella syndrome). The control group consisted of 17 normal age- and sex-matched children (two boys, 15 girls). Analyzed parameters included pituitary height, length, width, midsagittal cross-sectional area, calculated volume, and shape. The shape was assessed by a pituitary grading system and two other shape indexes (length-to-height and length-to-width ratios). Pituitary grade was defined by the concavity of the upper pituitary surface (grade 1 = marked concavity, grade 2 = mild concavity, grade 3 = flat, grade 4 = mild convexity, grade 5 = marked convexity). RESULTS: Pituitary grade showed a highly significant difference among groups (p < .001). Area, height, and length-to-height ratio were significantly different (p < .05), whereas length, width, length-to-width ratio, and volume were not. There was no significant difference in any of the variables compared between idiopathic and nonidiopathic groups. When selected variables (pituitary grade, area, height, length) in the central precocious puberty group were stratified by bone age and findings on pelvic sonograms, patients with advanced bone age had a significantly higher pituitary grade (p < .01) and had a tendency toward a greater pituitary length. Pituitary size and shape correlated with the hormonal profile. CONCLUSION: Change in pituitary grade is the most helpful variable for the diagnosis of central precocious puberty in a prepubertal child. A high pituitary grade (4 or above) is highly predictive of central precocious puberty, with the highest specificity and positive predictive value, but with low sensitivity. The use of combinations of high pituitary grade with two other positive findings (height and area greater than 1 SD from the respective means in the control group) improves the sensitivity, specificity, and predictive value of MR imaging in the diagnosis of central precocious puberty.

Analysis of Variance↗
PubMed1994

The role of magnetic resonance imaging in the diagnosis of soft tissue lesions.

Over the last decade MR imaging has gained widespread acceptance as the modality of choice for initial evaluation of a soft tissue mass. Although MR imaging generally does not predict the histologic nature of a mass, significant data are accumulating on MR imaging features useful in the diagnosis of several benign conditions and a few malignant ones. Soft tissue masses that do not demonstrate tumor-specific features on MR imaging should be considered indeterminate and possibly malignant and a biopsy should be obtained. This article reviews the literature and elaborates on soft tissue conditions where MR imaging features can suggest an accurate diagnosis of a soft tissue mass. The article also reviews other important applications of MR imaging as well as recent developments in pulsing sequences and MR spectroscopy. The major series studying the diagnostic value of MR imaging in soft tissue masses is discussed and compared.

Connective Tissue Diseases↗
PubMed1992

Treatment options in primary Ewing's sarcoma of the spine: report of seven cases and review of the literature.

Primary Ewing's sarcoma of the spine is reviewed, and seven cases are presented. Ewing's sarcoma of the spine is a rare condition that appears with a clinical triad of local pain, neurological deficit, and a palpable mass. The clinical picture, imaging characteristics, and management are discussed. The definitive management of Ewing's sarcoma of the spine, as in other locations, could include three main modalities: surgery, radiotherapy, and combination chemotherapy. In the presence of acute neurological decompensation, decompressive surgery via an appropriate approach should be performed. Because Ewing's sarcoma is usually sensitive to chemotherapy, initial chemotherapy, in neurologically stable patients, could be attempted first without surgical resection. Further management could then be gauged according to the response.

Adolescent↗
PubMed1991

Phenytoin-induced agranulocytosis: a nonimmunologic idiosyncratic reaction?

Agranulocytosis is a rare side effect of phenytoin treatment. We describe the case of an elderly man who developed agranulocytosis 2 weeks following initiation of phenytoin treatment, on no cytotoxic drugs or any other medications except decadron. The white blood cell count was 300/mm3 with absent granulocytes. The liver enzymes were also noted to be newly elevated. Complete workup showed no evidence of infection. The patient was managed as a case of neutropenic fever and phenytoin was discontinued. A bone marrow biopsy showed absent granulocyte precursors after myelocytes, and an antigranulocyte antibody titer was negative, which suggests a direct toxic effect rather than an immunologic phenomenon. Both agranulocytosis and hepatitis were readily reversible on phenytoin cessation.

Agranulocytosis↗
PubMed1991

A case of clozapine-induced neuroleptic malignant syndrome.

The treatment of psychotic symptoms in patients with a previous history of neuroleptic malignant syndrome (NMS) remains a dilemma. The authors describe a case in which clozapine caused NMS in a schizophrenic man who had previously experienced NMS during treatment with various antipsychotics. To their knowledge, this is the first report of "classical" NMS caused by clozapine alone.

Antipsychotic Agents↗
PubMed1990

Locked facets in the thoracic spine: report of three cases and a review.

Facet dislocation is a rare finding in the thoracic spine. This article presents three cases of bilateral locked facets in the thoracic region. Two were due to car accidents and the third was secondary to a vertical fall. The level of the injury was T2-T3 in two cases and T9-T10 in the third. Two patients were completely paraplegic on admission, whereas the third was neurologically intact. All patients had various associated injuries and fractures. The diagnosis of locked facets was not suspected in any of the cases, but was later made by computerized tomography with parasagittal reconstructions. All patients underwent surgery. The radiological diagnosis was confirmed intraoperatively in two cases. The facets were relocated by manual traction in one case and by Harrington distraction in the other. Fixation and fusion were performed in all three. Stability and vertebral alignment were achieved in all cases postoperatively.

Accidents, Traffic↗
PubMedDate not supplied

Dialysis grafts arterial plug: retrieval using the tulip sheath device in vitro.

The "arterial plug" is a resistant thrombus that frequently persists at the arterial anastomosis of clotted hemodialysis grafts following thrombolytic therapy. We studied the physical and morphological characteristics of the plug and determined the feasibility of transcatheter removal in vitro using the tulip compression thrombectomy system. Sixteen thrombus plugs were recovered during surgical thrombectomy of clotted human dialysis grafts. The physical and gross physical characteristics of all plugs were analyzed. Eight specimens were evaluated microscopically. Transcatheter compression thrombectomy of eight plugs was attempted in vitro. Each plug was embedded in a polyvinyl tube filled with newly clotted blood and connected to a flow circuit. First, balloon-assisted aspiration thrombectomy (BAT) of soft thrombus was performed, while sparing the distal-most segment containing the plug. The tulip sheath was then introduced facing the "arterial end" of the tube. The thrombus segment containing the plug was pulled back into the tulip mesh using either a 3 Fr Fogarty balloon catheter or a self-expanding rake. The tulip was closed to compress and remove the trapped plug. Near-complete thrombectomy of soft clot was achieved in all tested tubes. Compression and retrieval of the entire arterial plug was successful in all except one, where only partial compression of the plug occurred, presumably due to fibrotic changes. No fragmentation or embolization occurred in the remaining procedures. Spongy consistency was noted in 94% of the specimens. Microscopic evaluation showed organized layered thrombus with compaction in five plugs. Transcatheter removal of a thrombus plug is feasible in vitro using the tulip compression-thrombectomy system.

Arteriovenous Shunt, Surgical↗
PubMedDate not supplied

Percutaneous balloon-assisted aspiration thrombectomy of clotted hemodialysis access grafts.

PURPOSE: To present experience with percutaneous balloon-assisted aspiration thrombectomy (BAT) for the treatment of patients with clotted hemodialysis access grafts. MATERIALS AND METHODS: BAT was performed with use of 7-F intravascular sheaths and a Fogarty balloon catheter. It was tested with an in vitro flow-circuit model. Twenty consecutive BAT procedures were performed in 15 patients with clotted grafts. The balloon catheter was advanced through the sheath to the arterial anastomosis. The balloon was inflated and withdrawn while suction was applied from the sideport to recover thrombus. The procedure was repeated for the venous limb. BAT was used alone in 12 procedures and in combination with urokinase in eight procedures. RESULTS: Almost complete thrombectomy was achieved in all tubes (in vitro), with very low venous and arterial embolic fractions. Technical success (restored graft thrill and almost complete thrombectomy) was achieved in 18 cases (90%). Clinical success (patency after 1 week of dialysis) was achieved in 17 cases (85%). CONCLUSION: Percutaneous BAT is feasible in recently clotted dialysis grafts.

Arteriovenous Shunt, Surgical↗
PubMedDate not supplied

Repositionable vascular occluder: experimental comparison with standard Gianturco coils.

PURPOSE: To evaluate the efficacy and recanalization rates of a newly designed vascular occlusion device. MATERIALS AND METHODS: The self-expanding vascular occluder was braided from fine nitinol wires and filled with polyester fibers. The device was delivered through a 6-F polyethylene introducing sheath with use of a delivery cable with a microscrew adaptor. Comparison was made between one occlusion plug and two Gianturco coils placed in the corresponding contralateral arterial segment in nine dogs and six pigs. The mean diameter of the targeted vessels was 4.8 mm +/- 0.8. Two animals were killed immediately after occlusion, and the remaining 13 animals underwent follow-up angiography at 1 week and/or 1 month, after which the animals were killed and the vessels were explanted for gross and histopathologic examination. RESULTS: Significantly shorter time-to-occlusion was achieved with the nitinol plug compared with two Gianturco coils (1.73 minutes +/- 1.28 vs 5.73 minutes +/- 6.18; P = .021). The recanalization rate at 1 month was also significantly lower (36.4% vs 81.8%, P = .027). The occlusion time was strongly dependent on the target artery diameter with Gianturco coils (R = .79, P = .0007), and not with the nitinol plug. CONCLUSION: The nitinol vascular occluder appears highly effective and reliable, with one plug resulting in significantly faster and longer lasting occlusions compared with two Gianturco coils. The new device can be repositioned prior to release, therefore allowing optimal positioning.

Alloys↗