Reverse echelon node and a lymphatic ectasia in the same patient during breast lymphoscintigraphy: the importance of injection and imaging technique.

Lymphoscintigraphy, along with triangulated patient body marking, can serve as a guide for surgeons during sentinel lymph node harvesting. Unique drainage patterns have been noted, especially with areolar or intradermal based injections, which are becoming increasingly popular. The images lymphoscintigraphy provide have been invaluable in delineating these patterns. The authors present a case that simultaneously illustrates two separate points in the same patient, a reverse echelon node and a lymphatic ectasia. To our knowledge, this combination has never been described in the same patient. Perilesional and areolar-cutaneous junction injections were performed sequentially and generated these patterns that could potentially have resulted in added morbidity and a false-negative sentinel node if not realised before surgery. Lymphoscintigraphy added valuable information in the management of this patient, which can occasionally present with complex patterns of activity during sentinel node harvesting.

The role of (111)In Capromab Pendetide (Prosta-ScintR) immunoscintigraphy in the management of prostate cancer.

(111)In Capromab Pendetide (ProstaScintR) is a whole murine antibody that is reactive with prostate specific membrane antigen (PSMA), a glycoprotein on the surface of normal and abnormal prostate epithelium. It has proven to be of great value in assisting management decisions in prostate cancer patients who initially present with high risk for metastatic spread, or who develop a picture of recurrent disease after surgery or radiation therapy. Patterns of metastatic lymphatic spread have correlated well with autopsy reports in the literature. Unfortunately, other imaging study and/or histologic confirmation of scintigraphic findings has been difficult to obtain. Prostascint's role in predicting durable complete response (DCR) in postoperative patients having salvage radiotherapy to their prostate fossa is very promising. Further investigative work in larger patient populations is needed to confirm these early results.

Incidental recognition of left subclavian vein obstruction on renal scintigraphy.

In a renal transplant recipient with persistently poor graft function, the flow phase of a renal scan incidentally revealed multiple venous collaterals with focally increased vascular activity near the left lobe of the liver (quadrate lobe). This was initially assumed to represent superior vena cava (SVC) obstruction. A renal biopsy was contemplated to exclude acute rejection because of a nondiagnostic flow phase (loss of a bolus effect). However, because the possibility of venous obstruction at the level of the subclavian and/or brachiocephalic veins (without involving the SVC) also existed, another renal scan was performed, with injection of radiotracer into the contralateral arm. This showed a patent SVC and reasonably preserved renal perfusion consistent with acute tubular necrosis. Subsequently, left subclavian vein obstruction was identified. The graft function improved with conservative management for acute tubular necrosis. These findings illustrate the danger of considering only SVC obstruction when collateral flow patterns and focal hot spots in the liver are present.

Enhanced lung scan diagnosis of pulmonary embolism with the use of ancillary scintigraphic findings and clinical correlation.

Analysis of the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) and modified PIOPED studies has suggested that an experienced observer is capable of more accurate lung scan interpretation than the less experienced individual. This has been attributed to the use of unique Gestalt factors not contained in published diagnostic algorithms, which are acquired through extensive experience in reviewing and interpreting lung scans. How fully these factors can be codified and transmitted to less experienced observers is uncertain; however, there is a large body of published data that attempts to convey fine points of lung scan interpretation, including a large body of ancillary scintigraphic findings and a number of refinements in the application of diagnostic algorithms. Review of these factors will accelerate the training of less experienced readers. Finally, an understanding of lung scan language and an appreciation of clinically relevant factors, particularly pretest probability, will maximize the reader's ability to use the lung scan in managing patients who are suspected of having pulmonary embolic disease.

A normal variant on Tl-201 and Tc-99m MIBI whole-body imaging: the superior right atrial wall (auricle) and superoanterior right ventricular wall are often seen as mediastinal lesions.

PURPOSE: The authors have often observed on Tl-201 and Tc-99m sestamibi (MIBI) scans in patients with thyroid cancer a small focus of increased uptake in the right midparasternal region (focus A) or sometimes in the lower mid chest at the level of the lower sternum (focus B) just inferomedial to focus A. The objective of this study was to assess the frequency of this finding on Tl-201 MIBI studies, to assess the incidence of true pathologic lesions corresponding to these foci, and to identify their nature. MATERIALS AND METHODS: One hundred ten whole body Tl-201 studies using 4 mCi (148 MBq) and 84 MIBI studies using 20 mCi (740 MBq: first-pass, planar, and SPECT images) were reviewed. The appearance of either focus A or focus B on three orthogonal SPECT images was correlated with an atlas of cross-sectional anatomy and computed tomography. If focus A was seen on the immediate static image (obtained at the end of the first-pass acquisition without moving the patient), this image was coregistered with a selected image from the first-pass study showing the superior vena cava and also with another selected image showing the ascending aorta. RESULTS: Focus A was seen in 40% of Tl-201 scans and in 49% of MIBI scans, whereas focus B was seen in 20% of Tl-201 scans and 39% of MIBI scans. On correlation of the SPECT images with a cross-sectional anatomy atlas, focus A and focus B invariably corresponded to the superior portion of the right auricle and basal superoanterior right ventricular wall, respectively. These myocardial regions are prominent and sometimes appear as discrete foci because they are considerably thicker than other parts of the right atrial and right ventricular muscle, respectively, and because they are seen partly end-on in the anterior projection. CONCLUSIONS: The superior portion of the right auricle and basal superoanterior right ventricular myocardium often appear as isolated foci on whole-body Tl-201 and MIBl scans. Neither focus should be interpreted as a metastatic lesion in patients with possible cancer or as an ectopic parathyroid adenoma in patients with hyperparathyroid disease.

Technical aspects of performing lymphoscintigraphy: optimization of methods used to obtain images.

Sentinel node detection is an important part of the clinical management of newly diagnosed melanoma. Now there is a similar or even greater enthusiasm for sentinel node evaluation in patients with breast carcinoma. However, controversies exist regarding the dose, volume, and route of administration. Even the role of lymphoscintigraphy itself, in contrast to using only a hand-held gamma probe during surgery for sentinel node detection, is being debated. Nevertheless, many centers and surgeons find that lymphoscintigraphy images are valuable in the treatment of patients and they use lymphoscintigraphy as a guide during surgery and to confirm the results obtained with the hand-held probe. Centers just beginning to use lymphoscintigraphy may find the images especially useful. Given this fact, the authors wanted to define the practical and technical aspects of performing lymphoscintigraphy in patients with breast cancer and examined various methods for the optimization of the technique of image acquisition. The suggested technique is generally free of the controversies noted above and applies to most patients. It includes various maneuvers that aim to improve the rate of sentinel node visualization using the gamma camera and the accuracy of node detection. The recommendations presented here should prove useful for both those experienced and for those centers just beginning to use the technique of lymphoscintigraphy.

Refinement of the positive predictive value of gallbladder nonvisualization after morphine administration for acute cholecystitis based on the temporal pattern of common bile duct activity.

UNLABELLED: The authors previously reported two major patterns in the time-activity curve of the common hepatic bile duct (BD) after morphine administration in patients with gallbladder nonvisualization. The first pattern consists of a gradual increase in BD activity (of variable duration) occurring during a simultaneous decrease in liver parenchymal activity (BD increase), representing the physiologic effects of morphine administration. The second pattern consists of a continuous decrease in BD activity that parallels the activity in the liver parenchyma (BD decrease), representing lower or no physiologic effects of morphine administration. The authors hypothesize that gallbladder nonvisualization associated with a continuous decrease in BD activity after morphine administration will have a lower positive predictive value (PPV) for acute cholecystitis than gallbladder nonvisualization associated with an increase in BD activity. METHODS: Thirty-six patients who had morphine-augmented cholescintigraphy were divided into two groups: 19 with BD increase after morphine administration and 17 with BD decrease. RESULTS: Of the 36 patients, 22 had acute cholecystitis. The positive predictive value (PPV) of gallbladder nonvisualization was 61%. All of the remaining 14 had chronic cholecystitis. Of 19 patients with BD increase, 15 had acute cholecystitis (PPV = 79%), whereas only 7 of 17 patients with BD increase (PPV = 41 %) had acute cholecystitis (P = 0.023 by the one-tailed and 0.038 by the two-tailed Fisher exact tests). CONCLUSIONS: Gallbladder nonvisualization after morphine administration with the pattern of BD decrease is not as reliable (intermediate probability in this series) for the diagnosis of acute cholecystitis as is nonvisualization of the gallbladder in patients with a pattern of BD increase (high probability).

Use of radioimmunoscintigraphy with indium-111-labeled CYT-356 (ProstaScint) scan for evaluation of patients for salvage brachytherapy.

PURPOSE: Indium 111 capromab pendetide radioimmunoscintigraphy (ProstaScint) has been used to detect occult recurrent carcinoma after radical prostatectomy. MATERIALS AND METHODS: We evaluated the role of ProstaScint in 24 men with rising prostate-specific antigen (PSA) level following definitive radiation therapy to differentiate between local and distant recurrence in this patient population. RESULTS: ProstaScint scan detected prostatic uptake only in 16 patients, extraprostatic uptake in 5, both prostatic and extraprostatic uptake in 1, and no uptake in 2. Ten of 21 patients with prostatic uptake had positive biopsies, 5 had negative biopsies, and 6 were not biopsied. Two of the three patients with negative scans had positive biopsies, and the third patient was not biopsied. Three patients had evidence of osseous metastasis on radionuclide bone scan, two corresponding to the sites detected on ProstaScint. All three patients had abnormal uptake beyond the prostatic fossa with (n =2) or without (n = 1) prostatic uptake. There were no positive bone scans in patients without extraprostatic uptake on ProstaScint. CONCLUSIONS: ProstaScint scan is useful in detecting occult recurrence outside the prostate in patients with rising PSA following radiation therapy. Compared to data from radical prostatectomy, ProstaScint scans in these patients reveal a higher prevalence of abnormal uptake in the prostate and less frequent extraprostatic uptake.

Effect of prior radiopharmaceutical administration on Schilling test performance: analysis and recommendations.

UNLABELLED: Previously administered diagnostic and therapeutic radiopharmaceuticals may interfere with performance of the Schilling test for prolonged periods of time. Additionally, presence of confounding radionuclides in the urine may not be suspected if baseline urine measurements have not been performed before the examination. METHODS: We assumed that a spurious contribution of counts corresponding to 1% of the administered Schilling dose would begin to contribute clinically significant interference. Based on the typical amounts of radiopharmaceuticals administered, spectra of commonly used radionuclides and best available pharmacokinetic models of biodistribution and excretion, we estimated the interval required for 24-hr urinary excretion of diagnostic and therapeutic radiopharmaceuticals to drop below this threshold of significant interference. RESULTS: For previously administered 99mTc-based radiopharmaceuticals and 123I-Nal, the interval required for urinary levels of activity to fall below thresholds of allowable interference are between 2-5 days. For 67Ga-citrate, several 111In compounds, 131I-MIBG and 201Tl-thallous chloride, periods of 12-44 days are estimated. Estimates for 131I-Nal vary greatly between 4 and 115 days, depending on the amount administered, and the degree of thyroid uptake. CONCLUSION: Patients should be interviewed before performing the Schilling test to ensure that interfering radiopharmaceuticals have not been recently administered. The estimates developed in this paper can serve as guidelines for the necessary waiting time between prior radiopharmaceutical administration and the Schilling examination.

Appearance of a hepatic hemangioma on prostate immunoscintigraphy. Value of early images.

In this case, the authors describe the appearance of hemangioma, the most common benign tumor of the liver, on early and delayed in-111 CP antibody images. The early immunoscintigraphic images show intense blood pool activity comparable in appearance to labeled RBC imaging, the current procedure of choice for confirming the diagnosis of hemangioma. In combination with disappearance of blood pool activity on the late scintigraphic images, these findings are pathognomonic for hemangioma and sufficiently distinct from the appearance of hepatic metastases on in-111 labeled antibody images to obviate the need for further confirmatory diagnostic studies.

Accuracy of measurement of dual-isotope Schilling test urine samples: a multicenter study [corrected].

UNLABELLED: As a component of our quality assurance program, this multicenter study was performed to characterize the magnitude and types of error present in measurement of typical dual-isotope Schilling test (DIST) urine samples. METHODS: A panel of three simulated DIST urine samples was formulated corresponding to diagnoses of normal excretion, malabsorption and pernicious anemia and was distributed to eight hospitals in our regional area (three novice and five experienced users). Count-rate data and urine volume measurements from each site were analyzed for accuracy against the predicted values and a carefully measured gold standard and were correlated with the methodology and equipment used. RESULTS: Three of 24 results were uninterpretable due to an overly low ratio of intrinsic factor bound to free vitamin B12 excretion (B/F ratio), inconsistent with possible diagnoses. In 20 of 21 interpretable samples, results corresponded to the appropriate diagnoses, with typical values noted in 18 of the cases and slightly atypical yet diagnostic values seen in the remaining two cases. In only one sample did values correspond to an erroneous diagnosis (low normal or partial malabsorption rather than pernicious anemia). The four major discrepancies (test failure or misdiagnosis) were largely attributable to blunders and were limited to two of the three novice sites and to a single experienced site which had grossly inaccurate raw data (background greater than sample counts). CONCLUSION: Quantitation of vitamin B12 excretion in DIST urine samples is a reliable method of evaluation when performed by reasonably experienced and competent clinical laboratories. Improved accuracy may be obtained by increasing the stochastic certainty of the count data and by more careful measurement of the sample and urine volumes.