J. Kevin Smith
University of Alabama at Birmingham
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Featured researches published by J. Kevin Smith.
European Journal of Radiology | 2002
Mark E. Lockhart; J. Kevin Smith; Philip J. Kenney
Adrenal pathology may be discussed based on hormonal functionality of the adrenals, appearances on imaging modality, or pathological determination. There are three main categories of adrenal function. Hyperfunctional states include Conns or Cushings syndrome. Lesions with normal function may be detected incidentally. Hypofunctional states may occur from idiopathic Addisons disease or some bilateral adrenal pathology. The most common modalities for characterization of adrenal pathology are non-enhanced CT, often followed by contrast CT or chemical shift MRI. The common appearance on non-enhanced CT is a well-defined homogeneous lesion with low-density due to the microscopic fat present and adrenal adenomas. When density criteria are not met, many of these may be characterized as adenomas by washed out of contrast or signal decrease using in phase and out-of-phase MRI sequences. Other non-invasive modalities may incidentally discover adrenal lesions, but are not typically used in the work-up. NP-59 is an uncommonly used nuclear medicine technique which is very specific for adenoma when correlated with pathology on other imaging studies. In the rare cases where non-invasive imaging is non-specific, fine needle aspiration or core biopsies may be necessary. However, biopsies have associated risks including infection and hemorrhage. The imaging appearance of an adrenal lesion is often specific such that further imaging is not necessary. These lesions include adrenal adenoma, pheochromocytoma, myelolipoma, adrenal cyst, and some large adrenocortical carcinomas. However, the findings in lesions such as metastasis, smaller primary adrenal carcinomas, lymphoma, granulomatous disease, and many adenomas are not as specific. In the proper clinical situation, follow-up imaging may be necessary, or biopsy may be warranted.
American Journal of Roentgenology | 2007
Mark E. Lockhart; Franklin N. Tessler; Cheri L. Canon; J. Kevin Smith; Matthew Larrison; Naomi S. Fineberg; Brandon P. Roy; Ronald H. Clements
OBJECTIVE The purpose of this study was to evaluate the sensitivity and specificity of seven CT signs in the diagnosis of internal hernia after laparoscopic Roux-en-Y gastric bypass. MATERIALS AND METHODS With institutional review board approval, the CT scans of 18 patients (17 women, one man) with surgically proven internal hernia after laparoscopic Roux-en-Y gastric bypass were retrieved, as were CT studies of a control group of 18 women who had undergone gastric bypass but did not have internal hernia at reoperation. The scans were reviewed by three radiologists for the presence of seven CT signs of internal hernia: swirled appearance of mesenteric fat or vessels, mushroom shape of hernia, tubular distal mesenteric fat surrounded by bowel loops, small-bowel obstruction, clustered loops of small bowel, small bowel other than duodenum posterior to the superior mesenteric artery, and right-sided location of the distal jejunal anastomosis. Sensitivity and specificity were calculated for each sign. Stepwise logistic regression was performed to ascertain an independent set of variables predictive of the presence of internal hernia. RESULTS Mesenteric swirl was the best single predictor of hernia; sensitivity was 61%, 78%, and 83%, and specificity was 94%, 89%, and 67% for the three reviewers. The combination of swirled mesentery and mushroom shape of the mesentery was better than swirled mesentery alone, sensitivity being 78%, 83%, and 83%, and specificity being 83%, 89%, and 67%, but the difference was not statistically significant. CONCLUSION Mesenteric swirl is the best indicator of internal hernia after laparoscopic Roux-en-Y gastric bypass, and even minor degrees of swirl should be considered suspicious.
The American Journal of Gastroenterology | 2003
Desiree E. Morgan; J. Kevin Smith; Kidaday Hawkins; C.Mel Wilcox
OBJECTIVE:Pancreatic duct stenting is now recognized as a treatment option for a number of pancreatic disorders. Although stent-induced ductal changes may result, there is little information regarding the frequency of these stent-induced changes in chronic pancreatitis and their relationship to stent occlusion and clinical response. Our objectives were to evaluate pancreatic ductal changes after endoscopic stenting in patients with preexisting radiographic evidence of chronic pancreatitis and to evaluate the relationships between ductal changes, pain response, and stent patency.METHODS:Twenty-five consecutive patients had 40 stent placement episodes. Main pancreatic duct diameter, pancreatitis grade, preexisting obstructive lesions, and stent-induced strictures were recorded. Pain response and stent patency were correlated with main pancreatic duct caliber change using χ2 analysis.RESULTS:In 28 (70%) of 40 episodes, main pancreatic duct caliber increased or was unchanged after stenting; pain improved in 20 (71%) of 28. Pain improved in six (50%) of 12 patients with smaller ducts after stenting. Stent patency was documented upon retrieval in 34 episodes; most stents were occluded. Stent-induced strictures developed in 18% of 40 stent episodes.CONCLUSION:Main pancreatic duct caliber after endoscopic stenting was not a good indicator of pain response or stent patency; main pancreatic duct was often larger, and even with stent occlusion, patients’ symptoms were frequently improved. Stent-induced strictures were infrequent, compared with values previously reported in the literature.
Brain Research | 1990
J. Kevin Smith; Kirk W. Barron
Abstract The purpose of this study was to compare the responsiveness of the rostral and caudal ventrolateral medulla in spontaneously hypertensive (SH) and normotensive Wistar-Kyoto (WKY) rats to microinjection of l -glutamate, and to estimate tonic output of these areas by microinjecting the neurotoxin tetrodotoxin. Rats were anesthetized with 1.25 g/kg urethane s.c., implanted with arterial (femoral) and venous (femoral) catheters, artificially ventilated and paralyzed with gallamine triethiodide (10 mg/kg). Using a ventral approach to the brainstem, the mean arterial pressure and heart rate responses to microinjection (30 nl) of l -glutamate (1, 10 and 100 mM) and tetrodotoxin (10 μM) into the rostral and caudal ventrolateral medulla were compared in SH ( n = 7) and WKY ( n = 7) groups. Microinjection of l -glutamate into the rostral ventrolateral medulla produced equivalent increases in mean arterial pressure (maximum+33 ± 3and+36 ± 6 mm Hg, SH and WKY groups respectively) and minimal changes in heart rate. Similar administration of l -glutamate into the caudal ventrolateral medulla caused decreases in mean arterial pressure and heart rate; changes in mean arterial pressure were significantly greater in the SH group than in the WKY group (−52.3 ± 2.9 mm Hg for SH,−22.6 ± 2.6 mm Hg for WKY). Bilateral microinjection of tetrodotoxin into the caudal ventrolateral medulla produced significantly larger increases of mean arterial pressure in WKY rats (+8 ± 4vs+46 ± 8 mm Hg for SH vs WKY). These data indicate that SH rats may have a lower tonic activity of neurons in the caudal ventrolateral medulla, resulting in a lower restraining influence on sympathetic outflow in the SH rat. (Supported by: HL 36552 and KY-THRI 5-42078).
Radiologic Clinics of North America | 2003
J. Kevin Smith; Philip J. Kenney
Trauma is a major cause of death and disability and renal injuries occur in up to 10% of patients with significant blunt abdominal trauma. Patients with penetrating trauma and hematuria, blunt trauma with shock and hematuria, or gross hematuria warrant imaging of the urinary tract specifically and CT is the preferred modality. If there is significant perinephric fluid, especially medially, or deep laceration, delayed images should be obtained to evaluate for urinary extravasation. Most renal injuries are minor, including contusions, subcapsular and perinephric hematoma, and superficial lacerations. More significant injuries include deep lacerations, shattered kidney, active hemorrhage, infarctions, and vascular pedicle and UPJ injuries. These injuries are more likely to need surgery or have delayed complications but may still often be managed conservatively. The presence of urinary extravasation and large devitalized areas of renal parenchyma, especially with associated injuries of intraperitoneal organs, is particularly prone to complication and usually requires surgery. Active hemorrhage should be recognized because it often indicates a need for urgent surgery or embolization to prevent exsanguination.
Brain Research | 1990
J. Kevin Smith; Kirk W. Barron
This study was designed to compare the cardiovascular influences of the rostral ventrolateral medulla (RVLM) and the caudal ventrolateral medulla (CVLM) in young (5-6 weeks) spontaneously hypertensive (SH) and normotensive Wistar-Kyoto (WKY) rats. SH and WKY groups had similar pressor and depressor responses to microinjection of L-glutamate into the RVLM and the CVLM, respectively. In addition the results of this study indicate a reduced tonic sympathoinhibitory function of the CVLM in young SH rats, which may contribute to the development of hypertension in the spontaneously hypertensive rat.
Radiologic Clinics of North America | 2003
Mark E. Lockhart; J. Kevin Smith
CT is a robust, rapid means of evaluation for a wide spectrum of urologic disorders. The evaluation of renal trauma, urologic malignancy, urolithiasis, and vascular anatomy is well suited to CT techniques. Subtle adjustments in the technical parameters and timing of the study, however, can optimize the evaluation based on the clinical setting. As CT is more widely used, often repeatedly on an individual patient, radiation exposure must be minimized while still obtaining diagnostic image quality.
Hpb | 2015
Rojymon Jacob; Falynn Turley; David T. Redden; Souheil Saddekni; Ahmed Kamel Abdel Aal; K.S. Keene; Eddy S. Yang; Jessica G. Zarzour; David N. Bolus; J. Kevin Smith; Stephen H. Gray; Jared A. White; Devin E. Eckhoff; Derek A. DuBay
OBJECTIVES The optimal locoregional treatment for non-resectable hepatocellular carcinoma (HCC) of ≥ 3 cm in diameter is unclear. Transarterial chemoembolization (TACE) is the initial intervention most commonly performed, but it rarely eradicates HCC. The purpose of this study was to measure survival in HCC patients treated with adjuvant stereotactic body radiotherapy (SBRT) following TACE. METHODS A retrospective study of patients with HCC of ≥ 3 cm was conducted. Outcomes in patients treated with TACE alone (n = 124) were compared with outcomes in those treated with TACE + SBRT (n = 37). RESULTS There were no significant baseline differences between the two groups. The pre-TACE mean number of tumours (P = 0.57), largest tumour size (P = 0.09) and total tumour diameter (P = 0.21) did not differ significantly between the groups. Necrosis of the HCC tumour, measured after the first TACE, did not differ between the groups (P = 0.69). Local recurrence was significantly decreased in the TACE + SBRT group (10.8%) in comparison with the TACE-only group (25.8%) (P = 0.04). After censoring for liver transplantation, overall survival was found to be significantly increased in the TACE + SBRT group compared with the TACE-only group (33 months and 20 months, respectively; P = 0.02). CONCLUSIONS This retrospective study suggests that in patients with HCC tumours of ≥ 3 cm, treatment with TACE + SBRT provides a survival advantage over treatment with only TACE. Confirmation of this observation requires that the concept be tested in a prospective, randomized clinical trial.
European Journal of Radiology | 1997
Philip J. Kenney; Wlad T. Sobol; J. Kevin Smith; Desiree E. Morgan
OBJECTIVE Investigation has shown that the most useful MRI finding for the detection of breast cancer is enhancement following in travenous contrast. However, many widely different imaging protocols have been used. The purpose of this study is to explicate factors that affect the signal intensity of breast lesions after intravenous gadolinium. METHODS AND MATERIALS A computer model was developed using equations based on published data. The effect of gadolinium on breast tissues was calculated using the model with appropriate values for baseline tissue relaxation times, relaxivity of gadolinium at the given field strength and concentration of gadolinium based on published data, for the TR, TE, flip angle and field strength of several published sequences used for enhanced breast MRI. RESULTS The computer model allows comparison of the performance of different sequences, which can be displayed graphically. These vary in their performance, largely dependent on T1 weighting. Enhancement is also affected by the baseline of the T1 of the lesion and sensitivity of the sequence to gadolinium. Malignant lesions demonstrate greater observed enhancement than predicted when assuming symmetric distribution of contrast, indicating there is greater accumulation of gadolinium, accounting for the differential enhancement between benign and malignant lesions. CONCLUSIONS MRI sequences vary greatly in their demonstration of enhancement after intravenous gadolinium contrast. Numerical diagnostic criteria such as % signal intensity change must be interpreted with care when using a different sequence than that on which the criterion was developed. There is preferentially greater accumulation of contrast in malignant lesions, whether due to angiogenesis or altered permeability.
Hpb | 2014
Mary K. Bryant; David P. Dorn; Jessica G. Zarzour; J. Kevin Smith; David T. Redden; Souheil Saddekni; Ahmed Kamel Abdel Aal; Stephen H. Gray; Devin E. Eckhoff; Derek A. DuBay
BACKGROUND Radiographical features associated with a favourable response to trans-arterial chemoembolization (TACE) are poorly defined for patients with hepatocellular carcinoma (HCC). METHODS From 2008 to 2012, all first TACE interventions for HCC performed at the University of Alabama at Birmingham (UAB) were retrospectively reviewed. Only patients with a pre-TACE and a post-TACE computed tomography (CT) scan were included in the analyses (n = 115). HCC tumour response to TACE was quantified via the the modified Response Evaluation Criteria in Solid Tumors (mRECIST) criteria. Univariate and multivariable analyses were constructed. RESULTS The index HCC tumours experienced a > 90% or complete tumour necrosis in 59/115 (51%) of patients after the first TACE intervention. On univariate analysis, smaller tumour size, peripheral tumour location and arterial enhancement were associated with a > 90% or complete tumour necrosis, whereas, only smaller tumour size [odds ratio (OR) 0.62; 95% confidence interval (CI) 0.48, 0.81] and peripheral location (OR 6.91; 95% CI 1.75, 27.29) were significant on multivariable analysis. There was a trend towards improved survival in the patients that experienced a > 90% or complete tumour necrosis (P = 0.08). CONCLUSIONS Peripherally located smaller HCC tumours are most likely to experience a > 90% or complete tumour necrosis after TACE. Surprisingly, arterial-phase enhancement and portal venous-phase washout were not significantly predictive of TACE-induced tumour necrosis. The TACE response was not statistically associated with improved survival.