Visualization of hepatic adenoma with Tc-99m di-isopropyl IDA.

A case of hepatic adenoma is reported, presenting as a defect on sulfur colloid liver image and visualized on a biliary scintigram. Although biliary imaging in the evaluation of sulfur colloid defects may be of value in selected patients, combination imaging in this case could not distinguish a benign from a malignant process.

Longterm follow-up of patients with suspected pulmonary embolism and a normal lung scan. Perfusion scans in embolic suspects.

There is widespread acceptance of the thesis that in a patient with suspected embolism, a normal perfusion lung scan excludes the diagnosis of acute pulmonary embolism. However, limited published data exist which validate this thesis. We have explored this question by longitudinal follow-up of 68 patients who were referred for lung scanning to rule out embolism and proved to have normal perfusion lung scans. Risk factors for venous thromboembolism among these patients were similar to those reported in prior series of patients with pulmonary embolism. Our data support the widely-held views that: 1) a normal perfusion lung scan excludes the diagnosis of clinically significant pulmonary emboli; 2) the diagnostic work-up for suspected pulmonary embolism need not extend beyond a normal perfusion scan; 3) anticoagulant therapy can be discontinued after a normal perfusion scan, except in the presence of documented venous thrombosis; and 4) a normal lung scan has the same value in ruling out embolism in man as does a normal pulmonary angiogram.

The qualitative I-131 Hippuran renogram. A potential problem.

The I-131 Hippuran renogram time activity curve is usually generated by assigning computer assisted regions of interest over each kidney. Qualitative whole kidney renogram curves can be misleading when there is a nonobstructed but dilated collecting system or asymmetrical excretion of the tracer from the renal collecting system. This problem can be minimized by generating an additional renogram curve from a region of interest assigned over each renal cortex.

The potential role of In-111 white blood cell scans in patients with inflammatory bowel disease.

In many institutions, the use of In-111 white blood cell (WBC) scans have become routine for abscess detection. Its use for the detection of bone and joint inflammation, renal disease, and myocardial infarction has also been reported. Two patients are presented whose In-111 studies were of major clinical value in the management of their inflammatory bowel disease. In one, the diagnosis was suggested, and in the second, the extent of disease was defined. The potential role of In-111 WBC imaging in inflammatory bowel disease--for diagnosis, staging, and monitoring response to therapy--are discussed. Possible pitfalls as well as a comprehensive prospective study are suggested.

Gallium-67-citrate uptake in a case of acne vulgaris.

A case of increased Ga-67 uptake in a patient with active acne vulgaris is reported. The scan was requested in a search for metastatic testicular carcinoma or bleomycin pulmonary toxicity. Careful clinical evaluation including physical examination was necessary in order to avoid an erroneous scan interpretation.

Visual determination of differential renal function.

Forty patients (43 studies) referred for determination of differential renal function were imaged 24 hours after intravenous administration of Tc-99m-2, 3 DMSA. Visual assessment of relative renal uptake was estimated independently by three observers at three different hospitals from analog images on standard x-ray film. The results were compared with the relative DMSA uptake obtained by summing counts in computer-assisted regions of interest placed over each kidney. There was excellent correlation between the visual estimates of each observer and the computer-generated values (r = 0.98, 0.96, and 0.98, respectively). If a computer is not available, good visual estimates of differential uptake still may be obtained when static imaging agents such as DMSA are administered.

False-positive Tl-201 SPECT studies in patients with left bundle branch block. Frequency and clinical significance.

This study reports on the frequency and clinical significance of false-positive thallium studies in the interventricular septum in patients with left bundle branch block. In a 3-year period, 93 studies were performed on patients with complete left bundle branch block and sinus rhythm. Of these, 29 had a reversible septal defect; 17 are scored false-positive although only six had angiographic proof of normal left anterior descending coronary arteries. We conclude that thallium scintigraphy is indicated in patients with left bundle branch block, but caution is justified when reversible ischemia is demonstrated scintigraphically.

The 24-hour Tl-201 image in dual isotope myocardial perfusion scintigraphy: clinical utility and prognostic significance.

This study assessed the effect on clinical decision making and the possible prognostic significance of the 24-hour Tl-201 image in patients undergoing Tl-201-MIBI dual-isotope myocardial scintigraphy. The records of all patients who underwent 24-hour Tl-201 imaging as part of their myocardial perfusion study from 1994 to 1996 were reviewed. Follow-up evaluations were obtained from the referring physician or by direct patient contact. Fifty-six patients underwent a total of 57 studies; four patients were lost to follow-up. Of the 53 studies evaluated, 29 showed no change between the standard rest images and the 24-hour images; these patients were reported to have myocardial scar. Of these 29 patients, 25 were treated medically without further evaluation; 24 of these 25 patients remained stable. Four of the 29 patients had further evaluation; 2 patients had coronary artery bypass graft, 1 had a stent placed, and 1 remained stable. Twenty-four patients showed definite improvement or normalization of their study results by 24 hours; they were reported as ischemic. Of these 24 patients, 11 were treated medically without further evaluation; 9 remained stable, whereas 2 had adverse events. The remaining 13 patients required further evaluation; 4 remained stable, whereas 9 had adverse events (4 = increasing angina; 1 = stent; 1 = rotoblator; 2 = percutaneous transluminal coronary angioplasty; 1 = death). Twenty-four-hour imaging contributes to clinical decision making and may identify a subset of patients at risk for subsequent complications.

Positive In-111 white cell scan in a patient with multiple metastases.

A case of increased uptake of In-111-labeled leukocytes in bony metastases from adenocarcinoma of the prostate is presented. Bone scintigraphy, subsequent to the white cell study, showed virtually identical abnormalities as the indium scan. Clinical course and laboratory data supported the diagnosis of widespread metastatic carcinoma. Although the exact cause(s) is unclear, possible mechanisms are discussed.

The "hot" patella.

Increased patellar uptake on bone scans is seen quite commonly but the possible or probable etiologies of this finding have not been previously well described. A review of 100 consecutive bone scans showed that the incidence of bilateral "hot" patellae is 15%. Identified etiologies include osteoarthritic degenerative disease (35%), fracture, possible metastatic disease, bursitis, Paget's disease, and osteomyelitis. The value of careful history, physical examination, and radiographs is stressed.

Localization of a parathyroid adenoma by the addition of pinhole imaging to Tc-99m sestamibi dual-phase scintigraphy. Report of a case and review of experience.

Scintigraphy using Tc-99m has been shown to be highly sensitive in localizing abnormal parathyroid glands in patients with hyperparathyroidism. False-negative studies most often are attributed to glandular size or location. The authors report a case of negative parathyroid imaging using standard dual-phase technique, which was converted to a positive study by the addition of a pinhole view. During a 1-year period, the authors systematically added an anterior-pinhole image of the neck to all equivocal or negative Tc-99m studies. Five of 19 patient studies were pinhole-image positive and standard-image negative or equivocal. In selected patients undergoing Tc-99m scintigraphy for hyperparathyroidism, the addition of a pinhole view may enhance study sensitivity and the confidence in interpretation.

The feasibility of performing 133Xe ventilation imaging following the perfusion study.

The 99mTC Compton scatter contribution from the perfusion lung study to the subsequent 133Xe ventilation scan was quantitated in 15 consecutive patients undergoing both studies. Maximum contribution during the wash-in phase occurred during the first 10 seconds; thereafter, 99mTc Compton scatter averaged less than 10% of the total counts accumulated for a 133Xe image. The contribution during wash-out gradually increased to a maximum of 36% at 4 minutes in a normal subject. The authors conclude that a properly performed 133Xe ventilation study may immediately follow the 99mTc perfusion lung scan without significant image degradation.

Influence of perfusion and ventilation scans on therapeutic decision making and outcome in cases of possible embolism.

We examined the influence of perfusion (Q) and ventilation (V) scans on therapeutic decision making and outcome among 229 patients referred for lung scans because embolism was suggested and found that specific V/Q scan patterns strongly influenced postscan decisions regarding initiation, maintenance or cessation of heparin therapy. These therapeutic decisions bore a relationship to outcome (recurrences and death) and disclosed decision-making deficits that need remedy by future investigational and educational efforts.

Abnormal 99mTc-PIPIDA scans mistaken for common duct obstruction.

99mTc-PIPIDA scans were obtained in three patients with acute abdominal pain. The appearance of the scans suggested partial common duct obstruction. Two patients underwent surgery. One had acute appendicitis and the second had infarction of the distal ileum. In both cases, the gallbladder and biliary tract were normal. The third patient had been treated with morphine, which is known to increase biliary tract pressure and may cause contraction of the sphincter of Oddi. An ultrasound study of the gallbladder was normal and all symptoms resolved within 24 hours. Subsequently, three additional patients without biliary disease have been seen who had similar hepatobiliary scans. All three had received meperidine prior to the study. It is concluded that acute abdominal disease or the administration of morphine sulfate or meperidine can result in a scan pattern suggesting partial distal common duct obstruction in the absence of gallbladder or biliary tract disease.

In-111-leukocyte scintigraphy for detection of infection associated with peritoneal dialysis catheters.

In-111-labeled leukocytes were administered to 13 patients on continuous ambulatory peritoneal dialysis in order to locate catheter-associated infections. Using a marker to indicate the catheter exit site, infections of the catheter tunnel were correctly identified prior to surgery in 4 patients with relapsing peritonitis and infections of the exit site were diagnosed in 5 out of 7 patients. There were no false positives or negatives as documented by surgery or follow-up. The authors conclude that In-111-leukocyte scintigraphy appears to be accurate in diagnosing peritoneal infections of the dialysis catheter tunnel.