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.

Solitary thyroid nodule. Comparison between palpation and ultrasonography.

OBJECTIVE: To determine the accuracy of clinical palpation in the diagnosis of solitary thyroid nodule in comparison with ultrasonographic findings. METHODS: From a computerized database of 1774 patients with the diagnosis of nodular thyroid disease made from January 1990 through December 1991 at our institution, we retrieved and reviewed the medical records of the 193 patients who underwent ultrasonography of the thyroid (42 patients with multinodular glands on palpation were excluded). Nodules were categorized as "solitary" or "dominant nodule of a multinodular gland." Concordance rates were measured between results of palpation and ultrasonographic findings. RESULTS: Of 151 patients included in the study, 78 had solitary nodules on ultrasonography and 73 had multiple nodules. Of those with multiple nodules, 49 had two nodules and 24 had three or more nodules. Of clinically palpable nodules, 89% were 1 cm or greater in diameter. In 72% of the patients with multiple nodules, the other nodules not identified on palpation were less than 1 cm in diameter. The overall concordance rate between the size of the solitary nodule or the dominant nodule in a multinodular gland estimated with clinical palpation and the actual size seen on ultrasonography was 72%. The relationship between multiple nodules and malignancy was not statistically significant. CONCLUSIONS: Our results suggest that (1) a palpable solitary nodule represents a multinodular gland in about 50% of patients, (2) clinical palpation is less sensitive than thyroid ultrasonography in identifying multiple nodules, and (3) palpation is reliable only if a nodule is at least 1 cm in diameter. We recommend that small, occult (impalpable) thyroid nodules not be considered clinically important; they do not warrant further evaluation unless ultrasonographic features suggest malignancy or the nodule increases in size.

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.

Untreated rupture of the tunica albuginea.

A patient with untreated rupture of the tunica albuginea underwent surgical exploration 6 weeks after acute scrotal trauma. A layer of epithelium had grown across the bulging seminiferous tubules, and no further surgical repair was necessary. This spontaneous repair phenomenon has not previously been reported pictorially in the human testis. The recommended treatment of testicular rupture is surgical exploration and repair.

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.

Indications, technique, and efficacy of alcohol injection of enlarged parathyroid glands in patients with primary hyperparathyroidism.

BACKGROUND: Percutaneous alcohol ablation of the parathyroid gland (PAAP) has been proposed as an alternative treatment for primary hyperparathyroidism in patients unsuitable for surgery. The current study aimed to determine the (1) selection criteria, (2) associated morbidity, and (3) efficacy of PAAP. METHODS: From 1987 to 1998, 36 patients with primary hyperparathyroidism (mean age 65 years) underwent PAAP. The indications for PAAP were (1) medical comorbidity, (2) technically unsafe reoperative surgery, (3) partial ablation of a single remaining gland, and (4) patient choice. RESULTS: There were no long-term complications. Two patients had temporary recurrent laryngeal nerve injury and 4 had temporary hypocalcemia. Over a median follow-up of 16 months, 12 (33%) of the patients remained eucalcemic. For analysis purposes patients were separated into 2 separate groups: 29 with attempted complete ablation and 7 with partial ablation of a single remaining gland only. Ten of the complete ablation group (34%) remained eucalcemic. In the partial ablation group only 2 remained eucalcemic, but all had adequately controlled serum calcium levels. CONCLUSION: PAAP should be considered for hyperparathyroid patients with excessive reoperative morbidity or prohibitive medical comorbidity or those in whom the intent is to partially ablate a single remaining enlarged gland. In these patients close follow-up of serum calcium is required, and repeat treatments may be necessary because recurrence of hypercalcemia is likely.

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.

Ultrasound-guided intervention: expanding horizons.

Ultrasound-guided intervention has enjoyed a period of unprecedented growth because its many advantages over other guidance modalities have been recognized. The decreased procedure time, increased accuracy, and safety of procedures performed under ultrasound guidance are of obvious benefit to radiologist and patient alike for all interventional applications. Lesions once considered unsafe to sample are now reasonably approached with ultrasound guidance. As equipment technology continues to improve and radiologists increasingly recognize the benefits of guiding procedures with ultrasound, the shift of procedures away from CT and fluoroscopic guidance will continue and ultrasound guidance will become the guidance method of choice for most interventional procedures.

Thyroid imaging techniques.

Nuclear medicine, ultrasound, CT, and MRI are imaging methods that can be used to evaluate the thyroid gland. All these techniques give structural information about the thyroid gland and show the location and size of thyroid nodules. Nuclear medicine scanning also adds functional information about nodules. In many practices, however, FNA has supplanted imaging methods as the primary method of thyroid nodule evaluation because it is safe, inexpensive, and results in a better selection of patients for operation. Imaging studies are very useful in the setting of recurrent thyroid cancer. Ultrasound is extremely sensitive in the detection of recurrent malignancy in regional cervical lymph nodes and as a guide in performing a biopsy of these nodes. CT is very useful in identifying distant metastases in the chest and abdomen. Nuclear medicine scanning can detect functioning distant metastases when the metastases are from differentiated thyroid cancers. MRI can be used to evaluate the possibility of recurrent thyroid cancer; however, because of its relatively high cost, it is used less frequently than other imaging methods.

Thyroid and parathyroid imaging.

This article reviews the current roles of imaging in the diagnosis of thyroid and parathyroid disorders, with an emphasis on ultrasound evaluation. Imaging of the thyroid and parathyroid can be performed with nuclear medicine, ultrasound, CT, and MRI. Indications for thyroid and parathyroid imaging studies have recently changed. The availability of experienced endocrine surgeons, as well as the development of accurate laboratory tests, fine-needle aspiration (FNA) biopsy, and high-resolution ultrasound, have dramatically influenced the evaluation of thyroid and parathyroid disease. In patients with thyroid nodular disease, a clinical examination by an experienced clinician with appropriate lab values and palpation-guided FNA is the current diagnostic protocol of choice. Ultrasound evaluation of high-risk patients and ultrasound-guided FNA both augment this protocol when necessary. In patients with diffuse thyroid glandular disease, radionuclide imaging and color Doppler sonography both can be used for evaluation. When preoperative imaging is clinically necessary, sonography or scintigraphy can be used for parathyroid adenoma localization in patients with primary hyperparathyroidism. The recent development of technetium-99m sestamibi as a parathyroid imaging agent has improved the sensitivity of scintigraphy for parathyroid adenoma localization. Ultrasound and radionuclide imaging have also become valuable imaging techniques for parathyroid localization in patients with recurrent or persistent hyperparathyroidism.

Imaging of gastrointestinal neuroendocrine tumors.

Gastrointestinal neuroendocrine tumors are rare neoplasms that cause classic clinical syndromes because of the excess secretion of specific gastrointestinal hormones. The two most important tumors clinically are insulinomas and gastrinomas. The clinical management of patients with these disorders usually involves the localization and surgical removal of the responsible tumor. Many radiological techniques can be used for tumor localization, including preoperative and intraoperative ultrasound, endoscopic ultrasound, CT, MRI, radionuclide scanning, angiography, and venous sampling. However, there are conflicting claims as to the relative accuracy of these procedures, and many of these investigations are difficult to justify because of their high cost, degree of invasiveness, or lack of precise anatomic information that is obtained. If surgical resection of a neuroendocrine tumor is planned, intraoperative sonography should always be used to detect occult nonpalpable tumors and to discern the relationship of the tumor to vital adjacent pancreatic ductal anatomy. The choice of preoperative imaging is more controversial, and depends on the clinical problem, local expertise, and availability of imaging techniques. Sonography and contrast-enhanced helical CT are the most commonly used preoperative imaging methods, because of their relatively low cost and widespread availability. Radionuclide scanning with a somatostatin analogue, which is a relatively new procedure, may be valuable in patients with symptoms of tumor recurrence.

Ultrasound-guided biopsy and ablation in the neck.

Management and therapy of conditions of the thyroid, parathyroid glands, and cervical lymph nodes have evolved rapidly during the past 15 years. The development and continued improvement of high-resolution ultrasound (US) equipment, US-guided biopsy, and image-guided ablative techniques have fueled this change. These technical improvements and the knowledge and experience gained during this time have decreased the rate of unnecessary surgery in patients with thyroid nodules. They have also allowed more limited neck dissection in patients with parathyroid adenomas and have led to the development of US-guided ablative techniques that have eliminated the need for surgery in some cases. This article reviews the rationale and techniques of US-guided biopsy of the thyroid, parathyroid, and cervical lymph nodes. Established and evolving ablative techniques of these structures are also examined.

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.

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.

Penetrating injury to the brainstem after a nailgun accident: a case study.

Nonfatal penetrating injuries to the brainstem offer a unique opportunity to assess subcortical auditory pathway function. A case study of a patient suffering a severe nailgun accident is presented. Hearing sensitivity and acoustic reflexes were normal bilaterally, but word recognition was reduced for one ear. Auditory brainstem response results indicated waves I-IV were present bilaterally, but wave V was absent bilaterally. Results of vestibular findings indicated central pathology also. Results of audiologic, vestibular, radiologic, neurologic, and physical medicine examinations are discussed.

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.

Sonography guides biopsy and therapy in the neck.

Sonography is a powerful imaging method that can be used in the evaluation of patients with thyroid and parathyroid disease. The role of sonography in visualizing normal superficial neck structures and detecting small pathologic neck masses is being enhanced and expanded by its ability to accurately characterize suspected pathologic processes through precise percutaneous needle biopsy under real-time visualization.

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.

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.