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Biomedical subjects

Erick M Remer

Publications and source records attributed to Erick M Remer.

13 recordsLinked to original sources

Laparoscopic partial nephrectomy for incidental stage pT2 or worse tumors.

OBJECTIVES: To present our experience with laparoscopic partial nephrectomy (LPN) in patients with an incidentally detected Stage pT2, pT3a, or pT3b renal mass. METHODS: Of 525 patients undergoing LPN, 21 (4%) had pT2 or worse disease. LPN routinely involved en bloc excision of the overlying perirenal fat, along with the tumor and a healthy parenchymal margin. The preoperative computed tomography scans of these 21 patients were reviewed again by an unblinded radiologist to determine whether any suspicious radiologic signs of clinical Stage T2 or worse disease were present. RESULTS: The tumors were Stage pT2 in 1 (0.2%), pT3a in 19 (3.6%), and pT3b in 1 (0.2%). The mean pathologic tumor size was 3.7 cm (range 1.8 to 7.4). In the patient with pT3b disease, a tumor thrombus invading a renal vein branch was detected laparoscopically. The renal parenchymal and perirenal fat surgical margins were negative for cancer in all 21 patients (100%). The repeated nonblinded review of the preoperative computed tomography scans suggested definitive evidence, equivocal evidence, and no evidence of pT3a disease in 0, 5 (26%), and 14 (74%) patients, respectively, and suspicion for pT3b disease in the 1 patient. One patient with a 2.5-cm pT3a sarcomatoid renal cell carcinoma with negative surgical margins developed distant metastasis and died. During a mean follow-up of 29 months (range 1 to 58), the cancer-specific survival rate was 95%. CONCLUSIONS: The results of our study have demonstrated that adherence to surgical principles allows LPN to be performed for occult Stage pT2 and pT3 tumors with negative surgical margins and good oncologic outcomes. We have highlighted the importance of routine en bloc laparoscopic excision of the overlying perirenal fat along with the tumor, and intact specimen extraction, mirroring open surgery.

Aged↗

The predictive value of helical computed tomography for collecting-system entry during nephron-sparing surgery.

OBJECTIVES: To assess the ability of helical computed tomography (CT) including multiplanar reformatting and volume rendering (3D CT) to predict collecting system entry at surgery, as helical CT can be used to delineate renal tumour and normal renal anatomy before nephron-sparing surgery (NSS). PATIENTS AND METHODS: Knowledge of the possibility of collecting system entry during surgery might either dissuade some surgeons from NSS in elective situations or influence the operative approach or ablative technology in cases where NSS is imperative, or prepare the surgeon for the possibility of collecting system repair. We reviewed all 3D CT (349 scans) obtained before NSS at our institution over three consecutive years. Tumour size, central tumour extension, and presence of calyceal involvement were prospectively recorded at the time of 3D rendering. Collecting system entry was analysed for these three CT variables, and for three clinical variables (tumour side, size and surgical approach) collected retrospectively from the medical records. Multivariate logistic regression was used to assess the sensitivity, specificity, and positive and negative predictive values. RESULTS: Of 344 patients, 170 had collecting system entry reported at surgery. There were statistically significant associations between collecting system entry and central tumour location by CT (sensitivity 58.8%, specificity 80.5%, P < 0.001), calyceal involvement at CT (sensitivity 53.5%, specificity 78.2%, P < 0.001), and tumour size on CT of > 4 cm (sensitivity 39.4%, specificity 74.7%, P = 0.005). There were no significant associations with side or type of surgery (P > 0.83). CONCLUSION: Helical CT is a reliable predictor of calyceal entry at surgery.

Adolescent↗

Probe-ablative nephron-sparing surgery: cryoablation versus radiofrequency ablation.

Over the past decade, a number of probe ablative therapies have emerged for the treatment of patients with localized renal tumors. Cryoablation and radiofrequency ablation (RFA) have been studied in the greatest detail. We present the results of 164 laparoscopic cryoablations and 82 percutaneous RFAs performed in our institution and compare them retrospectively in terms of complications, impact on renal function, follow-up imaging, and oncologic outcomes. Comparison of cryotherapy versus RFA revealed that mean tumor size was similar (2.56 cm vs 2.51 cm); however, the cryoablation group had a greater number of anteriorly located tumors (39% vs 10%), as well as fewer central tumors (6% vs 37%) and fewer solitary kidneys (24% vs 49%). Mean thermal treatment time was 19.3 minutes versus 32.2 minutes in the cryoablation and RFA groups, respectively. Radiologic evidence of tumor recurrence or persistence of disease was noted in 3 patients (1.8%) who underwent cryoablation and in 9 (11.1%) who were treated with RFA. All of have been successfully treated with repeat ablation/nephrectomy, or they are currently under observation. Complication rates were minimal in both groups; no significant impact on mean serum creatinine levels was noted. Cancer-specific survival following cryotherapy was 98% at a median follow-up of 3 years and 100% for RFA at 1-year median follow-up. Cryoablation and RFA are developmental nephron-sparing options. Early results are encouraging for both forms of probe ablation in terms of early oncologic control, preservation of renal function, and low complication rates. Longer-term oncologic data are necessary so that the true value of these treatment modalities can be determined.

Adult↗

CT histogram analysis in pathologically proven adrenal masses.

OBJECTIVE: The purpose of this article is to evaluate a histogram analysis method for distinguishing adrenal adenomas from metastases, pheochromocytomas, and adrenocortical carcinomas on CT. MATERIALS AND METHODS: A pathology database was searched, and 335 adrenalectomies from 1995 to 2002 were identified. CT images were available for retrospective review in 187 patients (93 males, 94 females; age range, 15-84 years; mean age, 55.2 years) with 208 adrenal masses. This included 112 adenomas in 104 patients, 48 metastases in 39 patients, 40 pheochromocytomas in 36 patients, and eight adrenocortical carcinomas in eight patients. Histogram analysis was performed using a circular region of interest for mean attenuation, number of pixels, number of negative pixels (< 0 H), and percentage of negative pixels by two interpreters. Areas of necrosis were excluded from measurements. Observer agreement was calculated. RESULTS: In 72 of 76 (94.7%) and 63 of 72 (87.5%) adenomas, respectively, interpreters found attenuation values greater than 10 H contained negative pixels on unenhanced CT scans. None of the enhanced adenomas had mean attenuation less than or equal to 10 H, but 24 (38.7%) and 28 (45.2%), respectively, had negative pixels. Negative pixels were present in unenhanced and enhanced metastases, pheochromocytomas, and carcinomas. Using a 5% or 10% negative pixel threshold value to diagnose adenoma improved specificity but diminished sensitivity. Specificity for a 10% negative pixel threshold was approximately 88% for unenhanced CT scans and 99% for enhanced CT scans, with sensitivities of 71% and 12%, respectively. CONCLUSION: Although specificity for the diagnosis of adenomas on enhanced CT scans with histogram analysis was high when a 10% negative pixel threshold was used, low sensitivity likely limits clinical usefulness.

Adenoma↗

Renal cryoablation: outcome at 3 years.

PURPOSE: We report intermediate term oncological followup data on 56 patients undergoing laparoscopic renal cryoablation, of whom each completed a 3-year followup. MATERIALS AND METHODS: Since September 1997, 56 patients undergoing laparoscopic renal cryoablation have completed a followup of 3 years each. The postoperative followup protocol comprised serial magnetic resonance imaging (MRI) at 1 day, months 1, 3, 6, 12, 18 and 24, and yearly thereafter for 5 years. Computerized tomography guided needle biopsy of the cryolesion was performed 6 months postoperatively and repeated if MRI findings were abnormal. Followup data were obtained prospectively. RESULTS: For a mean renal tumor size of 2.3 cm mean intraoperative size of the created cryolesion was 3.6 cm. Sequential mean cryolesion size on MRI on postoperative 1 day, and at 3 and 6 months, and 1, 2 and 3 years was 3.7, 2.8, 2.3, 1.7, 1.2 and 0.9 cm, representing a 26%, 39%, 56%, 69% and 75% percent reduction in cryolesion size at 3 and 6 months, and 1, 2 and 3 years, respectively. At 3 years 17 cryolesions (38%) had completely disappeared on MRI. Postoperative needle biopsy identified locally persistent/recurrent renal tumor in 2 patients. In the 51 patients undergoing cryotherapy for a unilateral, sporadic renal tumor 3-year cancer specific survival was 98%. There was no open conversion, kidney loss, urinary fistula, dialysis requirement, or perirenal or port site recurrence in any patients. CONCLUSIONS: Three-year outcomes following renal cryoablation are encouraging. Longer term (5-year) data are necessary to determine the proper place of renal cryotherapy among minimally invasive, nephron sparing options.

Adult↗

Comparison of CT findings in symptomatic and incidentally discovered pheochromocytomas.

OBJECTIVE: The objective of our study was to determine the prevalence of incidental pheochromocytomas, whether their imaging characteristics differ from those of pheochromocytomas in symptomatic patients, and whether they differ from adenomas using CT densitometry. MATERIALS AND METHODS: The records from 335 adrenalectomies performed at our institution from 1995 to 2002 were reviewed, and 71 pheochromocytomas were identified. Thirty-three patients had CT examinations performed at our institution that were available for retrospective review. From electronic and hard-copy medical records, patient age and sex, the indications for imaging, and biochemistry activity were recorded. Pheochromocytomas were classified as symptomatic or incidental on the basis of clinical presentation. These groups were compared for differences in patient age, adrenal mass volume and maximal diameter based on CT dimensions, attenuation on unenhanced CT, attenuation on enhanced CT during the portal phase, the presence of calcifications, low attenuation or cystic changes, biochemical activity, and hypertension. Statistical significance was assessed with the Student's t test or chi-square test, as appropriate. RESULTS: Nineteen incidental (57.6%) and 14 symptomatic (42.4%) adrenal pheochromocytomas were in the study. There was a significant difference between the two groups as to whether hypertension was present (incidental, 10/19 [52.6%]; symptomatic, 14/14 [100%]; p = 0.0025). We found a trend toward calcification present in more symptomatic patients (incidental, 0/19 [0%]; symptomatic, 4/14 [28.6%]; p = 0.0670). No statistically significant difference was noted in the mean patient age (incidental, 51.7 years; symptomatic, 45.9 years), mean volume of the mass (incidental, 74.0 cm(3); symptomatic, 78.2 cm(3)), mean maximal diameter of the mass (incidental, 5.26 cm; symptomatic, 5.33 cm), mean attenuation on unenhanced CT (incidental, 36.6 H; symptomatic, 34.2 H), mean attenuation on enhanced CT (incidental, 93.7 H; symptomatic, 104.3 H), necrosis score or biochemical activity (incidental, 17/18 [94.4%]; symptomatic, 12/14 [85.7%]). No attenuation value of any pheochromocytoma was less than 10 H on unenhanced CT (median, 35 H; range, 17-59 H). CONCLUSION: In our study population, 57.6% of the pheochromocytomas were incidental, more than in most reported series. A history of hypertension was more frequent in the symptomatic group (p = 0.0025), but no radiologic parameters that allow differentiation of incidental and symptomatic pheochromocytomas were found. None of the pheochromocytomas had attenuation values of less than 10 H on unenhanced CT scans.

Adrenal Gland Neoplasms↗

Clinical utility of noncontrast computed tomography attenuation value (hounsfield units) to differentiate adrenal adenomas/hyperplasias from nonadenomas: Cleveland Clinic experience.

Radiological characterization of an adrenal tumor as adenoma may decrease the need for follow-up imaging studies, biopsies, and unnecessary adrenalectomies. We retrospectively reviewed 299 adrenalectomies in 290 patients at Cleveland Clinic Foundation over a recent 5-yr period to assess the value of noncontrast Hounsfield units (HU) in characterizing whether an adrenal mass is adenoma or nonadenoma. The mean (+/- SD) HU value for the adrenocortical adenoma/hyperplasia group was 16.2 +/- 13.6 and significantly lower (P < 0.0001) than primary adrenocortical cancers (36.9 +/- 4.1), metastases (39.2 +/- 15.2), and pheochromocytomas (38.6 +/- 8.2). The sensitivity and specificity for 10- and 20-HU cutoff values to differentiate adenomas/hyperplasias from nonadenomas were 40.5 and 100% and 58.2 and 96.9%, respectively. The size of the adrenal tumor had less value with only 40.7 and 81.3% sensitivity and 94.7 and 61.4% specificity for 2- and 4-cm cutoff values. A combination of less than or equal to 4-cm adrenal mass size and noncontrast computed tomography HU less than or equal to 20 had 42.1% sensitivity and 100% specificity. Our study, the largest with surgical histopathology as the gold standard for diagnosis, supports a noncontrast computed tomography attenuation value of 10 HU as a safe cutoff value to differentiate adrenal adenomas/hyperplasias from nonadenomas.

Adenoma↗

Three-dimensional volume-rendered helical CT before laparoscopic adrenalectomy.

Use of three-dimensional (3D) volume-rendered helical computed tomography (CT) in surgical planning before laparoscopic adrenalectomy was evaluated in a retrospective study. In 35 consecutive patients before laparoscopic adrenalectomy, 3D volume-rendered CT scans were created from helical CT scans. Videotapes that showed anterior, lateral, posterior, and posterocephalic approaches were assessed retrospectively. The relationship (not contacting, abutting, displacing, or invading) of adrenal masses to adjacent organs (diaphragm, liver, spleen, kidneys, stomach, pancreas, and vessels) was recorded and compared with findings in surgery reports. When such findings were available, they corresponded to those in the videotape. Three-dimensional volume-rendered CT successfully displayed the relationship of adrenal masses to adjacent anatomic structures and organs before laparoscopic adrenalectomy.

Adrenal Glands↗

Effect of intentional cryo-injury to the renal collecting system.

PURPOSE: We determined the short-term and long-term sequelae of intentional cryoablation of the renal pelvicaliceal system and evaluated whether continuous irrigation of the renal pelvicaliceal system with warm saline protects it against cryo-injury. MATERIALS AND METHODS: In 12 swine open bilateral renal cryoablation using an argon gas based system was performed to create a cryolesion in the lower pole that was intentionally extended into the collecting system. A single cryoprobe was used to create a 3 cm ice ball in group 1 (6 animals) and 2, 3 mm cryoprobes were used to create a 4.5 cm ice ball in group 2 (6). In all 12 right kidneys pelvicaliceal warming (range 38C to 42C) was performed using continuous retrograde saline irrigation through an indwelling 5Fr ureteral catheter. In all 12 left kidneys cryoablation was performed without pelvicaliceal warming. Real-time confirmation of caliceal involvement by the cryolesion was obtained by retrograde ureteropyelogram. Immediately after cryo-injury 6 left and 6 right kidneys were harvested for histology and the animals with a solitary kidney were followed for 1 to 3 months. RESULTS: Nadir cryoprobe tip temperature was -136C with a mean cryolesion time of 10.5 minutes. Cryolesion size was comparable in the right vs left kidneys in groups 1 and 2 (2.9 vs 3.0 and 4.7 vs 4.6 cm, respectively). Similarly cryoablation time was comparable between the right and left kidneys in groups 1 and 2 (11.3 vs 10.8 and 11.9 vs 12.2 minutes, respectively). Two animals died of aspiration pneumonia (1) and wound dehiscence (1). In all 10 surviving animals no instance of urinary extravasation was noted. At 1-month followup regrowth of normal urothelium occurred with some scarring of the lamina propria or underlying smooth muscle. Adjacent renal parenchyma was replaced by fibrous scar. At 3 months the cryo-injured collecting system was completely healed with a fibrous scar. There were no appreciable histological differences between the kidneys with or without warm pelvicaliceal irrigation. CONCLUSIONS: Our data suggest that absent physical puncture injury of the collecting system with the cryoprobe tip the cryodamaged renal collecting system heals by secondary intention in a watertight manner. These data have clinical relevance for facilitating cryoablation of a small, localized, central renal tumor in proximity to the pelvicaliceal system.

Animals↗

Imaging of chronic pancreatitis.

This article reviews the recognized findings of chronic pancreatitis on CT and endoscopic retrograde cholangiopancreatography. It also discusses more recently developed techniques including gadolinium-enhanced MR imaging, MR cholangiopancreatography, and endoscopic ultrasound. Variants of chronic pancreatitis and difficulties in differentiating pancreatic neoplasms from inflammatory pancreatic masses are also discussed.

Cholangiopancreatography, Endoscopic Retrograde↗

The utility of radiological imaging in nonalcoholic fatty liver disease.

BACKGROUND & AIMS: This prospective study evaluates the role of radiological modalities in establishing the diagnosis of nonalcoholic steatohepatitis (NASH). METHODS: Consecutive patients with biopsy-proven nonalcoholic fatty liver disease (NAFLD) were enrolled (2000-2001). Patients with other liver diseases and significant alcohol consumption (>20 g/day) were excluded. Clinicodemographic data were gathered at the time of liver biopsy. Each biopsy specimen was assessed by a hepatopathologist. Each patient underwent a limited abdominal ultrasonography (US), computerized tomography (CT), and magnetic resonance imaging (MRI). Films were interpreted by a radiologist who used a predetermined radiological protocol. Each radiological study was reread by the same radiologist and a second radiologist. RESULTS: Patients with NASH had greater aspartate aminotransferase levels (P = 0.03), greater ferritin levels (P = 0.05), more hepatocyte ballooning (P < 0.0001), and more fibrosis (P = 0.002). None of the radiological features distinguished between NASH and other types of NAFLD. No radiological modality detected the presence of hepatocyte ballooning, Mallory's hyaline, or fibrosis, which are important features in the diagnosis of NASH. The presence of >33% fat on liver biopsy was optimal for detecting steatosis on radiological imaging. CONCLUSIONS: Differences between NASH and nonprogressive NAFLD were not apparent with any radiological modality. Of the pathologic features important for establishing the diagnosis of NASH, only the severity of steatosis was reflected in these radiological modalities. Good intraobserver agreement was evident for each modality (US, CT, and MRI) that was superior to interobserver agreement.

Adult↗

Imaging for nephron-sparing surgery.

Nephron-sparing surgery is more technically demanding than conventional nephrectomy. The urologist can benefit from modern radiological methods to plan and monitor surgery and to provide post-surgical surveillance. This article describes how 3D volume renderings of CT and MRI data can be useful in planning nephron-sparing surgery, how intraoperative imaging can guide surgery and tumor ablation, and how CT and MRI can be used to monitor for recurrent disease and postoperative complications.

Humans↗