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Biomedical subjects

C C Reading

Publications and source records attributed to C C Reading.

At least 19 recordsLinked to original sources
PubMed1992

Endorectal sonography.

Endorectal sonography is a technique that has been developed recently to visualize the rectal wall and perirectal tissues with a high degree of clarity. Studies utilizing endorectal sonography in the preoperative staging of rectal carcinoma have reported an accuracy of between 67 and 92% in the visualization of the depth of tumor invasion in the rectal wall. This surpasses the accuracy reported for digital exam and other preoperative imaging methods such as CT and MRI. Perirectal lymphadenopathy is also well visualized by this method and guided biopsy of perirectal nodes has been reported. Precise preoperative staging of rectal carcinoma by endorectal sonography is an important technique that can: (1) improve surgical planning, (2) provide prognosis in nonsurgical candidates, and (3) select patients suitable for local excision therapy.

Adenocarcinoma↗
PubMed1990

Detection of somatostatin receptors in surgical and percutaneous needle biopsy samples of carcinoids and islet cell carcinomas.

Somatostatin (SS) receptor status was investigated in the tumor tissues from 62 patients with carcinoid tumors and 15 patients with islet cell carcinomas using receptor autoradiography techniques with two different iodinated somatostatin analogues as radioligands, a [Leu8, DTrp22, Tyr25]somatostatin-28 and a somatostatin octapeptide, Tyr3-octreotide. The carcinoid tumors were either primaries (n = 32) or metastases (n = 43), sampled as surgical specimens or as small needle liver biopsies. Fifty-four of 62 carcinoid patients had SS receptor-positive tumors (87%). All 15 islet cell carcinoma patients had positive tumors (4 primaries, 11 metastases), i.e., 3 vipomas, 3 insulinomas, 2 glucagonomas, 1 gastrinoma, 2 polyfunctional tumors, and 4 nonfunctioning tumors. Saturation and competition experiments on tissue sections revealed saturable, high affinity binding sites pharmacologically specific for bioactive SS analogues. In a majority of the tumors, the receptors were densely distributed and were always homogeneously found in the whole tumor. All except two tumors were labeled with both radioligands. Multiple liver metastases (n = 16) from three different patients were all shown to contain a comparable amount of receptors. SS receptors could be demonstrated even in very small tissue samples of liver metastases obtained by percutaneous liver biopsies (mean weight, 6.8 mg). The majority of the eight SS receptor-negative carcinoids were mainly bronchial carcinoids (n = 5), usually poorly differentiated. On the contrary, SS receptor-positive cases were never found to be anaplastic. All tumors except one from patients pretreated with octreotide (3 days to 3.8 years) were SS receptor positive. In the majority of carcinoids or islet cell carcinomas, the SS receptor status correlated with the in vivo biochemical response (hormone inhibition) to octreotide. These data demonstrate (a) the high prevalence of SS receptors in the primary tumors of both carcinoids and islet cell carcinomas, (b) their presence in metastases as well, (c) their continuous expression even during long term octreotide therapy, (d) the possibility of measuring SS receptors in percutaneous needle liver biopsies, and (e) the evidence of their functionality. This study therefore suggests that tumoral SS receptors may be the likely molecular basis for octreotide action and may be an important parameter for predicting the therapeutic efficacy of SS analogues in carcinoids and islet cell carcinomas.

Adenoma, Islet Cell↗
PubMed1990

Endorectal ultrasonographic staging of rectal carcinoma.

Endorectal ultrasonography is a valuable imaging method for examination of the rectum and perirectal tissues. We assessed 50 patients with known rectal carcinoma prospectively by using a 7.0-MHz endorectal transducer to determine the depth of invasion of the rectal wall by tumor and the presence of lymphadenopathy. Tumors were staged by using the Astler-Coller modification of the Dukes staging system, and the results were compared with histologic staging of the surgical specimen. Ultrasonography had an accuracy of 80%, a sensitivity of 92%, and a specificity of 76% for detection of invasion of the perirectal fat. Ultrasonography was sensitive in the detection of perirectal lymphadenopathy but was not specific in distinguishing benign from malignant nodes.

Adult↗
PubMed1990

Color and spectral Doppler mirror-image artifact of the subclavian artery.

The mirror-image artifact, which has been previously described in gray-scale sonographic imaging, is also readily visualized with both spectral and color Doppler flow imaging. In 10 consecutive healthy subjects, a mirror image of the subclavian artery was readily apparent at gray-scale, spectral Doppler, and color Doppler sonography. An experimental in vitro model was constructed to demonstrate that the lung apex, which is located immediately posterior to the subclavian artery, acts as the highly reflective acoustic interface to form this artifact. Knowledge of the presence of the mirror-image artifact should be helpful to the radiologist and sonographer in avoiding misinterpretation of this important pitfall in both spectral and color Doppler flow imaging of the subclavian region, where there is a plethora of branching vessels.

Humans↗
PubMed1989

Imaging-guided biopsy.

In the past 10 years, imaging-guided biopsy has become an accepted technique of tissue retrieval for pathologic analysis. Fluoroscopy, ultrasonography, computed tomography, and magnetic resonance imaging are the current methods of guiding biopsy procedures. Each modality has advantages and disadvantages for various organ systems. High accuracy rates and low complication rates can be expected. Cost savings and rapid reporting of results add to the value of these procedures.

Biopsy↗
PubMed1989

Current applications of color Doppler imaging in the abdomen and extremities.

Recent advances in ultrasound technology have resulted in the development of diagnostic instruments that combine cross sectional imaging with spectral and color flow Doppler analysis. These instruments have expanded the role of diagnostic ultrasonography in the assessment of disease states involving the extracranial carotid artery, the peripheral vascular system, and the major abdominal vessels. The current applications of color Doppler imaging (CDI) combined with conventional spectral Doppler are demonstrated.

Abdomen↗
PubMed1988

Reoperative parathyroid surgery.

Reoperation for persistent or recurrent primary hyperparathyroidism immediately connotes a complex clinical management problem. Successful cure of hypercalcemia is less frequent whereas complications are more common compared to initial explorations. Of 212 patients operated on at the Mayo Clinic from 1978 through 1986, 189 (89%) were cured. Sporadic disease, multiple endocrine neoplasia, and familial hyperparathyroidism were found in 183 (87%), 20 (9%), and 9 (4%) patients, respectively. Prior to the most recent reoperation, these patients had undergone from one to five operations. Preoperative localization examinations were performed in 192 patients (91%). Cervical high-resolution, real-time ultrasonography, computed tomography, and thallium-technetium scintigraphy had sensitivity rates of 87%, 56%, and 71%, respectively. When the tumor was localized preoperatively, the operative time and cost were significantly reduced compared to nonlocalized tumors. Cervical reexploration only was required in 154 (72%), combined cervical and mediastinal exploration occurred in 46 (22%), and mediastinal exploration only was performed in 12 (6%). There was no perioperative mortality; permanent hypoparathyroidism developed in 33 patients (16%), and six patients (2.9%) suffered permanent unilateral vocal cord paralysis. Anatomically, the most frequent site to find a missed parathyroid adenoma was in the normal location. The large majority of these glands were removed through a cervical incision although, on occasion, they were retracted from the anterior superior mediastinum or the low tracheoesophageal space. These data confirm that reoperative parathyroid surgery can be performed safely, with a rather high degree of success, but too-frequently results in a lifetime morbidity of hypoparathyroidism.

Adolescent↗
PubMed1988

Insulinoma: the value of intraoperative ultrasonography.

Ideally, surgical exploration for insulinomas would be met with uniform success in both finding and removing the tumor, incurring no postoperative mortality or morbidity. In reality, however, insulinomas remain undetected by even experienced surgeons in 10 to 20% of patients, including present-day series. Additionally, postoperative complications may occur in 10 to 25% of patients, principally related to the pancreatic dissection. Although dispensing with any attempt to preoperatively localize the tumor has been advocated, most authors agree that localization efforts are necessary and helpful. To review the results and surgical implications of current localization techniques, 41 adult patients who were surgically treated for insulinomas at the Mayo Clinic from 1980 through June 1987, were reviewed. Tumor size ranged from 5 mm to 4 cm, and the sensitivity of tumor localization using arteriography, computed tomography, preoperative and intraoperative ultrasonography were 55%, 27%, 59%, and 90%, respectively. Since the introduction of intraoperative ultrasonography into our clinical practice in 1982, all 29 of our adult patients' insulinomas have been identified with a combination of this technique and palpation by an experienced surgeon. There were no false positive interpretations with intraoperative ultrasonography, and tumors were imaged in four patients that were not palpable. In 18 of these 29 (62%) patients, the information gleaned from the images appeared to influence the surgical management. While there is no substitute for exploration by an experienced surgeon, his ability is enhanced by the addition of both preoperative and intraoperative ultrasonography.

Adenoma, Islet Cell↗
PubMed1988

Insulinoma. The value of intraoperative ultrasonography.

After establishing the diagnosis of an insulinoma, most surgeons prefer preoperative localization. Selective arteriography has long remained the gold standard for this purpose, but its use has been met with variable success. Despite various attempts at localization, insulinomas remain undetected in 10% to 20% of patients, and there may be a postoperative complication rate of at least 10% to 25%. To review the results and surgical implications of current localization techniques, 36 adult patients who were surgically treated for insulinomas at the Mayo Clinic, Rochester, Minn, from July 1982 through June 1987 were studied. The sensitivities of tumor localization using arteriography, computed tomography, and preoperative and intraoperative ultrasonography were 53%, 36%, 59%, and 90%, respectively. A subset of 29 patients underwent intraoperative ultrasonography, and all of these patients' insulinomas were identified with a combination of this technique and intraoperative palpation, with nonpalpable tumors being imaged in four patients. In 18 patients (62%), information obtained from the images appeared to influence the surgical management. While there is no substitute for exploration by an experienced surgeon, exploration appears to be enhanced by the addition of intraoperative ultrasonography, particularly during reoperation.

Adenoma, Islet Cell↗
PubMed1988

Localization of pancreatic insulinoma: comparison of pre- and intraoperative US with CT and angiography.

Methods of preoperative radiologic localization of insulinoma were compared in 52 patients, 44 of whom had solitary tumors. Examinations performed in these 44 patients were preoperative ultrasonography (US) in 28, angiography in 26, and computed tomography in 23. Prospective sensitivities were 61%, 54%, and 30%, respectively. Imaging sensitivities were lower for the eight patients with multiple insulinomas. In 28 of the 44 patients, intraoperative US was performed without the examiner being aware of the surgical findings. The sensitivity was 84%. Four insulinomas were not palpable but were visualized sonographically. The combined sensitivity of intraoperative US and surgical palpation for detecting solitary insulinomas was 100%. High-frequency intraoperative US is valuable for detecting occult solitary insulinomas and considerably useful for determining the proximity of insulinomas to the pancreatic and bile ducts.

Adenoma, Islet Cell↗
PubMed1988

US-guided biopsy of neck masses in postoperative management of patients with thyroid cancer.

High-frequency (10-MHz) sonography demonstrated a cervical mass or lymphadenopathy, or both, during postoperative follow-up of 52 patients who had undergone surgery for thyroid cancer. Percutaneous biopsy with ultrasonographic (US) guidance was performed in all 52 masses, 44 of which were nonpalpable. Malignant cells were obtained in 29 biopsies, and the results of 20 biopsies were negative, yielding benign lymphocytes only. Results in three biopsies were nondiagnostic due to hypocellular specimens. Therefore, 94% of biopsy results (49) of 52) were confidently assigned as either positive (56%) or negative (38%) for malignancy. There were no complications. High-frequency sonography can demonstrate clinically occult thyroid bed tumor recurrence and lymph node metastases. US-guided biopsy is an accurate and safe technique to confirm or exclude malignancy in patients at high risk of recurrence of thyroid cancer.

Adult↗
PubMed1988

Sonographically guided percutaneous biopsy of small (3 cm or less) masses.

Traditionally, sonographically guided percutaneous needle biopsy has been used for the biopsy of large, superficial, and cystic masses. Today, however, many think that small, solid masses also can be biopsied accurately. Real-time sonographically guided biopsies of 126 consecutive solid masses that were less than or equal to 3.0-cm in diameter (less than or equal to 1.0 cm, 24; 1.1-2.0 cm, 42; 2.1-3.0 cm, 60) were performed to diagnose primary or secondary neoplasm. These masses were located in a variety of anatomic regions (abdomen, 92; neck, 31; breast, two; extremity, one). Clear visualization of the biopsy needle was accomplished by continuous real-time monitoring of the needle's position, primarily by using linear, phased-array transducers, large-caliber needles (18- to 19-gauge, when possible), and an echogenic screw stylet inserted coaxially within the biopsy needle. The correct cytologic/histologic diagnosis was established in 91% of the masses (less than or equal to 1.0 cm, 79%; 1.1-2.0 cm, 88%; 2.1-3.0 cm, 98%). No complications other than mild, localized discomfort were encountered. Our experience suggests that sonographically guided biopsy is a highly accurate and safe procedure that can be used to establish the diagnosis in solid masses that are 3.0 cm or less in diameter if proper techniques are used to clearly visualize the biopsy needle.

Biopsy, Needle↗
PubMed1987

Medullary thyroid carcinoma: role of high-resolution US.

Medullary thyroid carcinoma accounts for 10% of thyroid malignancies. Accurate determination of the extent of disease is important because surgery is required for initial treatment and recurrence. High-resolution (10-MHz) ultrasonography (US) of the neck was used to study 15 patients with medullary thyroid carcinoma; nine of the 15 had undergone thyroidectomy but had biochemical evidence of tumor recurrence. Metastatic cervical lymph nodes were detected with US in all 12 patients who had metastatic nodes at surgery, although these nodes were palpable in only four. Punctate bright echogenic foci were seen within some of the nodes in nine of the 12 patients (75%). Similar bright echogenic foci were seen within the primary intrathyroid tumor in five of the six patients who had not yet undergone thyroidectomy (83%). Pathologically, these foci correlated with deposits of calcium surrounded by amyloid, which is characteristic of medullary thyroid carcinoma. US is useful for the detection of nonpalpable recurrence of cervical metastatic lymph nodes, and because it is noninvasive and relatively inexpensive, it should be the first imaging investigation performed after thyroidectomy.

Adult↗