The Role of Tc-99 m-MIBI Scan in the Assessment of the Cystic Thyroid Nodule

PurposeA non-surgical therapeutic option requires assurance that a cystic thyroid nodule with non-diagnostic cytology is benign. This work was undertaken to determine whether Tc-99 m-MIBI scan (MIBI) findings can guide the best therapeutic option with confidence.Material and MethodsWe studied 81 cystic non-functioning thyroid nodules with non-diagnostic fine-needle aspiration biopsy (FNAB) report classified according to ATA 2015 ultrasonography (US) patterns for suspicion of malignancy. All had a MIBI to assess metabolic activity within the nodule as well as histopathological diagnosis. Diagnostic value analysis of MIBI as compared to the US pattern was determined.ResultsNone of the 11 patients with US pattern of benign showed positive MIBI, and all had a histopathological report of benign. Diagnostic value of MIBI on US pattern of very low suspicion showed sensitivity, specificity, PPV, and NPV of 100%, 78.9%, 42.9%, and 100%, respectively.ConclusionOur data shows that the only approach to a safe non-surgical treatment option in a cystic nodule with non-diagnostic FNAB is when no metabolic activity is seen on MIBI.     

99mTc-MIBI scintigraphy in musculoskeletal tumors.

The aim of this study was to assess the value of 99mTc-hexakis2-methoxyisobutylisonitrile (MIBI) scintigraphy in patients with clinical and radiologic features of primary or metastatic musculoskeletal tumors. METHODS: The scintigraphic findings for 84 patients were compared with the surgical and histologic findings. Each patient underwent three-phase bone scanning with 99mTc-methylene diphosphonate (MDP) and dynamic and static MIBI scintigraphy. The MIBI scans were evaluated by visual and quantitative analysis. The count ratio of the lesion to the adjacent or contralateral normal area (L/N) was calculated from the region of interest drawn on the MIBI scan. The Mann-Whitney test was used to determine the differences between the uptake ratios of malignant and benign lesions. RESULTS: Although increased MDP uptake was not specific for bone malignancy, a significant difference was found between benign tumors (L/N = 1.22 +/- 0.43) and malignant tumors (L/N = 2.25 +/- 1.03) on MIBI scans. Sensitivity and specificity were 81% and 87%, respectively. Forty-six of 53 proven benign lesions did not show significant MIBI uptake. The negative predictive value was 88%. In all seven sites of pathologic fracture, significant uptake was seen. However, three malignant lesions were not detected by MIBI scintigraphy, whereas seven benign lesions showed false-positive results. CONCLUSION: The major diagnostic worth of MIBI scintigraphy is its high negative predictive value. Although not capable of replacing tissue biopsy as a definitive diagnostic modality for musculoskeletal neoplasms, MIBI scintigraphy does appear to have a role in better preoperative assessment and in distinguishing between pathologic and simple fractures.     

99Tcm-MIBI scintimammography in 300 consecutive patients: factors that may affect accuracy

We evaluated the diagnostic yield of 99Tcm-MIBI scintimammography in a relatively large series of consecutive patients referred for breast surgery on the basis of physical examination or mammogram. 99Tcm-MIBI uptake was correlated to tumour size, receptor status, neovascularity, proliferating activity, P-170 glycoprotein expression and the patient's gonadal state. Three hundred consecutive patients referred to our institution, with either a positive mammogram or a palpable mass, were entered into the study. All patients underwent 99Tcm-MIBI scintimammography. Pathological status was obtained after surgery in all patients. Breast cancer was diagnosed in 218 (73%) patients. The MIBI scan was positive in 89% (194/218) cancer patients and in 17% (14/82) of patients with benign masses (false-positives); the scan was negative in 24 (11%) cancer patients (false-negatives). The sensitivity of MIBI scintigraphy was higher for tumours > 1 cm (95 vs 48% in lesions < or = 1 cm) and in pre-menopausal women (95 vs 85%). Conversely, the specificity was better for lesions < 1 cm (100%) and in post-menopausal women (89%). The positive predictive value of MIBI scan was good both in small (< 1 cm) and large tumours (100% and 93%, respectively) and slightly modified by gonadal state (89% and 96% in pre- and post-menopausal state). The negative predictive value was unsatisfactory, especially in small tumours and in older patients. The diagnostic performance increased stratifying data for tumour size, indicating that lesion size is a major determinant in the diagnostic accuracy of MIBI scintimammography. We conclude that 99Tcm-MIBI scintimammography is useful in the diagnostic evaluation of young patients, because it can select patients for further invasive diagnostic procedures. In older patients, a positive 99Tcm-MIBI scan is highly suggestive of malignancy and might be an indication for surgery. In the case of a negative scan, biopsy is advisable given the poor negative predictive value. Small tumour size and a well-differentiated histotype characterize false-negative cases.     

The role of technetium-99m methoxyisobutylisonitrile scintigraphy in the differential diagnosis of cold thyroid nodules

Various diagnostic techniques have been successfully used in the clinical management of cold nodules; however, the decision on whether to employ surgery or a conservative treatment is not always easy. This study was designed to appraise the diagnostic value of technetium-99m methoxyisobutylisonitrile (MIBI) scintigraphy in the assessment of cold nodules detected using ^99mTc-pertechnetate. Fifty-two patients were included in the study. All had already been selected for surgery, based on their clinical and laboratory findings, including fine-needle aspiration biopsy. The total number of cold nodules on ^99mTc-pertechnetate scans was 59. The thyroid scan was performed 20-40 min after i.v. injection of 400 MBq of ^99mTc-MIBI. Uptake of MIBI in thyroid nodules was compared with that in the surrounding normal thyroid tissue, and a score of between 0 and 3 was assigned to each nodule as follows: 0, cold; 1, decreased; 2, equal; 3, hot. Definitive histology revealed nodular goitre in 24 cases, adenoma in 19, thyroiditis in 1, differentiated cancer in 12, medullary cancer in 2, and anaplastic cancer in 1. None of the degenerative nodules were hot on MIBI scan, while the adenomas showed a variety of MIBI imaging patterns, most frequently the score 3 pattern. In the diagnosis of differentiated thyroid cancer the sensitivities of score 3 and score 2+3 MIBI uptake patterns were 83% (10/12) and 100%, respectively. The score 3 MIBI uptake pattern had a specificity of 100% and a positive predictive value of 100% with respect to thyroid (benign and malignant) neoplastic diseases, whereas a specificity of 72% and a positive predictive value of 43% were observed in the detection of differentiated cancer. After a cold nodule had been detected using ^99mTc-pertechnetate, a second scan with high MIBI uptake increased by 7.8 times the probability that this nodule would be a differentiated cancer. In conclusion, ^99mTc-MIBI scintigraphy is a useful method in the differential diagnosis of cold thyroid nodules if the primary aim is to differentiate degenerative from neoplastic diseases rather than to differentiate benign from malignant nodules. High MIBI uptake considerably increases the probability of a differentiated thyroid cancer and facilitates immediate surgical removal, while decreased uptake actually excludes it. We suggest a combination of fine-needle aspiration biopsy and MIBI scan as a routine diagnostic approach to cold thyroid nodules. Received 12 January and in revised form 18 March 1999     

The role of technetium-99m methoxyisobutylisonitrile scintigraphy in the planning of therapy and follow-up of patients with differentiated thyroid carcinoma after surgery

The aim of this study was to investigate the possible role of technetium-99m methoxyisobutylisonitrile (MIBI) scan in planning post-surgical therapy and follow-up in patients with differentiated thyroid carcinoma (DTC). Four groups of DTC patients were considered: Group 1 comprised 122 patients with high serum thyroglobulin (s-Tg) levels and negative high-dose iodine-131 scan during follow-up who had previously undergone total thyroidectomy and ¹³¹I treatment. Group 2 consisted of 27 patients who had previously undergone total thyroidectomy and ¹³¹I treatment but were now considered disease-free; this group was considered as controls. Group 3 comprised 49 patients studied after total thyroidectomy but prior to ¹³¹I scan. Finally, group 4 consisted of 21 patients who had previously undergone partial thyroidectomy alone. MIBI scan, neck ultrasonography (US), and s-Tg measurements during suppressive hormonal therapy (SHT) were obtained in all patients. Neck and chest computed tomography (CT) or magnetic resonance imaging (MRI) was also performed in group 1 patients. In group 1, MIBI scan and US were very sensitive in detecting cervical lymph node metastases (93.54% and 89.24%, respectively). Furthermore, MIBI scan and US played a complementary role in several patients, yielding a global sensitivity of 97.84%. In contrast, CT/MRI sensitivity for cervical lymph node metastases was very low (43.01%). MIBI scan also showed a higher sensitivity than CT/MRI in detecting mediastinal lymph node metastases (100% vs 57.89%). Regarding distant metastases, MIBI scan provided results similar to those of conventional imaging (CT, MRI, ^99mTc-methylene diphosphonate bone scan). In group 2, no false-positive cases were observed with MIBI scan (100% specificity). In group 3, MIBI scan correctly identified all the ¹³¹I-positive metastatic foci, except in two patients with micronodular pulmonary metastases that were visualised with ¹³¹I scan. In contrast, both MIBI scan and US showed low sensitivity (46.15% and 61.53%, respectively) compared with ¹³¹I scan in detecting thyroid remnants. s-Tg was increased in all patients with distant metastases but only in 56% of those with lymph node metastases. Furthermore, s-Tg was increased in 21.42% of patients with thyroid remnants alone (false-positive results). In group 4, MIBI scan was the only examination capable of detecting at an early stage a mediastinal lymph node metastasis in one patient. We conclude that the integrated MIBI scan/neck US protocol: (a) can be proposed as a first-line diagnostic procedure in the follow-up of DTC patients with high s-Tg levels and negative high-dose ¹³¹I scan, and (b) may be helpful in the follow-up of DTC patients who undergo partial thyroidectomy alone. Moreover, the combined MIBI scan/neck US/s-Tg protocol appears to be highly sensitive in identifying patients with metastatic disease after total thyroidectomy and prior to ¹³¹I scan; consequently, it may play a prognostic role in distinguishing high-risk from low-risk DTC patients. However, due to the low sensitivity of MIBI scan and neck US in detecting thyroid remnants, this diagnostic approach cannot be used as a predictor of ¹³¹I scan results. Lastly, because of the high sensitivity of MIBI scan and neck US in revealing both functioning and non-functioning metastases, this integrated protocol might be helpful in the follow-up of high-risk DTC patients, particularly for the early detection of lymph node metastases in patients with undetectable s-Tg during SHT. Received 21 October and in revised form 20 December 1999     

99Tc(m)-tetrofosmin scintimammography for detecting breast cancer: a comparative study with 99Tc(m)-MIBI.

Scintimammography using 99Tc(m)-MIBI (99Tc(m)-sestamibi) has demonstrated promising results in the detection of breast cancer. Recently scintimammography using 99Tc(m)-tetrofosmin has been suggested as a better diagnostic tool and a more convenient agent to use in this condition. In this study we compared both agents in 35 consecutive women with abnormal mammographic or physical findings. Thirty-four of them underwent MIBI scan, followed by tetrofosmin scan 2 days later (performed on all 35 women). Within 2 weeks, a pathological diagnosis was obtained either by needle or open biopsy. In both scans the uptake ratio between the lesion and the background uptake was calculated. Twenty patients who underwent tetrofosmin scan and 19 patients with MIBI scan had malignant breast tumours, while 15 women had benign lesions. The sensitivity, specificity, positive and negative predictive values and total accuracy of the MIBI scan were 89.4%, 80%, 85%, 85.7% and 85.3%, respectively; almost identical values were obtained with tetrofosmin (90%, 80%, 85.6%, 85.7% and 85.7%, respectively). The uptake ratios in the MIBI and tetrofosmin scans were 1.68 +/- 0.52 and 1.7 +/- 0.47, respectively. No differences were found between the two scintimammographies in all the parameters examined. In conclusion, MIBI and tetrofosmin breast scans are accurate and equally efficient for the detection of breast malignancies.     

Core needle biopsy can minimise the non-diagnostic results and need for diagnostic surgery in patients with calcified thyroid nodules

Purpose

To evaluate the role of core needle biopsy (CNB) for calcified thyroid nodules.

Methods

Between October 2008 and July 2011, 264 patients underwent ultrasound-guided CNB for 272 calcified thyroid nodules at our institution. We retrospectively evaluated the incidence of technical failure, non-diagnostic readings, and the diagnostic performance of CNB, and analysed the relationship between the types of calcification and the CNB results. Finally, the incidence of diagnostic surgery was calculated.

Results

The incidence of technical failure was 1.1 % (3/275) and that of non-diagnostic results was 0.7 % (2/272). The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of CNB were 94.7 %, 89.5 %, 100 %, 100 %, and 90.2 %, respectively. There were no significant differences according to the calcification subtype for either the non-diagnostic results or the incidence of technical failure (P?>?0.99 and P?>?0.99). CNB could prevent diagnostic surgery for 92.9 % (13/14) of the patients who showed more than two non-diagnostic results in previous FNA.

Conclusions

CNB can minimise the non-diagnostic results as well as diagnostic surgery in patients with calcified thyroid nodules. Therefore, CNB may be used as a first-line diagnostic tool for calcified thyroid nodules rather than FNA.

Key points

? CNB results show the low incidence of technical failure (1.1 %, 3/275). ? CNB results show the low non-diagnostic rate (0.7 %, 2/272). ? There were no significant differences according to the calcification subtype. ? CNB can prevent unnecessary diagnostic surgery in 92.9 % (13/14).     

Thyroid nodules with initially non-diagnostic,fine-needle aspiration results: comparison of core-needle biopsy and repeated fine-needle aspiration

Objective

To evaluate the role of core-needle biopsy (CNB) by comparing the results of CNB and repeated fine-needle aspiration (FNA) for thyroid nodules with initially non-diagnostic FNA results.

Methods

From October 2008 to December 2011, 360 nodules – 180 consecutive repeated FNAs and 180 consecutive CNBs –– from 360 patients (83 men, 277 women; mean age, 54.4 years) with initially non-diagnostic FNA results were analyzed retrospectively. The incidence of non-diagnostic results, inconclusive results, diagnostic surgery, and diagnostic performance of repeated FNA and CNB were assessed, and factors affecting second non-diagnostic results were evaluated.

Results

CNB achieved a significantly lower non-diagnostic and inconclusive rate than repeated FNA (1.1 % versus 40.0 %, P?P?P?=?0.047). Multivariate logistic regression analysis showed that repeated FNA was the most important factor for second non-diagnostic results (OR?=?56.06, P?P?=?0.003).

Conclusions

CNB is more useful than repeated FNA for reducing the number of non-diagnostic and inconclusive results and for preventing unnecessary diagnostic surgery for thyroid nodules with initially non-diagnostic FNA results.

Key Points

? Core-needle biopsy achieved a lower number of non-diagnostic and inconclusive results. ? Core-needle biopsy achieved better diagnostic performance. ? Use of core-needle biopsy could prevent unnecessary diagnostic surgery. ? Repeated fine-needle aspiration was significantly associated with a second non-diagnosis.     

The role of technetium-99m methoxyisobutylisonitrile scintigraphy in the differential diagnosis of cold thyroid nodules.

Various diagnostic techniques have been successfully used in the clinical management of cold nodules; however, the decision on whether to employ surgery or a conservative treatment is not always easy. This study was designed to appraise the diagnostic value of technetium-99m methoxyisobutylisonitrile (MIBI) scintigraphy in the assessment of cold nodules detected using (99m)Tc-pertechnetate. Fifty-two patients were included in the study. All had already been selected for surgery, based on their clinical and laboratory findings, including fine-needle aspiration biopsy. The total number of cold nodules on (99m)Tc-pertechnetate scans was 59. The thyroid scan was performed 20-40 min after i.v. injection of 400 MBq of (99m)Tc-MIBI. Uptake of MIBI in thyroid nodules was compared with that in the surrounding normal thyroid tissue, and a score of between 0 and 3 was assigned to each nodule as follows: 0, cold; 1, decreased; 2, equal; 3, hot. Definitive histology revealed nodular goitre in 24 cases, adenoma in 19, thyroiditis in 1, differentiated cancer in 12, medullary cancer in 2, and anaplastic cancer in 1. None of the degenerative nodules were hot on MIBI scan, while the adenomas showed a variety of MIBI imaging patterns, most frequently the score 3 pattern. In the diagnosis of differentiated thyroid cancer the sensitivities of score 3 and score 2+3 MIBI uptake patterns were 83% (10/12) and 100%, respectively. The score 3 MIBI uptake pattern had a specificity of 100% and a positive predictive value of 100% with respect to thyroid (benign and malignant) neoplastic diseases, whereas a specificity of 72% and a positive predictive value of 43% were observed in the detection of differentiated cancer. After a cold nodule had been detected using (99m)Tc-pertechnetate, a second scan with high MIBI uptake increased by 7.8 times the probability that this nodule would be a differentiated cancer. In conclusion, (99m)Tc-MIBI scintigraphy is a useful method in the differential diagnosis of cold thyroid nodules if the primary aim is to differentiate degenerative from neoplastic diseases rather than to differentiate benign from malignant nodules. High MIBI uptake considerably increases the probability of a differentiated thyroid cancer and facilitates immediate surgical removal, while decreased uptake actually excludes it. We suggest a combination of fine-needle aspiration biopsy and MIBI scan as a routine diagnostic approach to cold thyroid nodules.     

Combined 99mTc-methoxyisobutylisonitrile scintigraphy and fine-needle aspiration cytology offers an accurate and potentially cost-effective investigative strategy for the assessment of solitary or dominant thyroid nodules

Purpose

Fine-needle aspiration (FNA) has revolutionised the care of patients with thyroid nodules and is the initial investigation of choice. However, as a result of nondiagnostic (Thy1) and nonneoplastic (Thy2) specimens, it remains an imperfect sole solution with a range of sensitivities and a high inadequate ratio. Therefore the British Thyroid Association (BTA) guidelines recommend a second FNA immediately for Thy1 specimens and 3–6 months later for Thy2 specimens. Patients must be followed up to exclude malignancy. In this study we assessed the performance of MIBI scintigraphy for diagnosing thyroid malignancy and the cost-effectiveness of a combined FNA/MIBI investigative strategy for the management of thyroid nodules.

Methods

The diagnostic performance of MIBI scintigraphy was calculated from a retrospective review of local data combined with a meta-analysis of the published literature. Decision tree analysis was used to calculate the cost-effectiveness of a combined FNA/MIBI investigative strategy compared to the BTA guidelines.

Results

From 712 patients, the sensitivity, specificity, PPV and NPV of MIBI scintigraphy for the diagnosis of malignancy were 96 %, 46 %, 34 % and 97 %, respectively. MIBI-based strategies were more accurate and associated with lower cost per patient (£1,855/€2,125 vs. £2,445/€2,801) and lower cost per cancer diagnosed (£1,902/€2,179 vs. £2,469/€2,828) with negligible change in life expectancy.

Conclusion

Due to its high NPV, MIBI scintigraphy can usefully exclude malignancy for Thy1 and Thy2 lesions. Its low specificity means MIBI scintigraphy cannot be recommended as a first-line investigation, but as a second-line investigation MIBI scintigraphy may lead to a lower rate of unnecessary thyroidectomies. Combined FNA/MIBI strategies are potentially cost-effective in the management of solitary or dominant thyroid nodules.     

The role of technetium-99m methoxyisobutylisonitrile scintigraphy in the planning of therapy and follow-up of patients with differentiated thyroid carcinoma after surgery

The aim of this study was to investigate the possible role of technetium-99m methoxyisobutylisonitrile (MIBI) scan in planning post-surgical therapy and follow-up in patients with differentiated thyroid carcinoma (DTC). Four groups of DTC patients were considered: Group 1 comprised 122 patients with high serum thyroglobulin (s-Tg) levels and negative high-dose iodine-131 scan during follow-up who had previously undergone total thyroidectomy and 131I treatment. Group 2 consisted of 27 patients who had previously undergone total thyroidectomy and 131I treatment but were now considered disease-free; this group was considered as controls. Group 3 comprised 49 patients studied after total thyroidectomy but prior to 131I scan. Finally, group 4 consisted of 21 patients who had previously undergone partial thyroidectomy alone. MIBI scan, neck ultrasonography (US), and s-Tg measurements during suppressive hormonal therapy (SHT) were obtained in all patients. Neck and chest computed tomography (CT) or magnetic resonance imaging (MRI) was also performed in group 1 patients. In group 1, MIBI scan and US were very sensitive in detecting cervical lymph node metastases (93.54% and 89.24%, respectively). Furthermore, MIBI scan and US played a complementary role in several patients, yielding a global sensitivity of 97.84%. In contrast, CT/MRI sensitivity for cervical lymph node metastases was very low (43.01%). MIBI scan also showed a higher sensitivity than CT/MRI in detecting mediastinal lymph node metastases (100% vs 57.89%). Regarding distant metastases, MIBI scan provided results similar to those of conventional imaging (CT, MRI, 99mTc-methylene diphosphonate bone scan). In group 2, no false-positive cases were observed with MIBI scan (100% specificity). In group 3, MIBI scan correctly identified all the 131I-positive metastatic foci, except in two patients with micronodular pulmonary metastases that were visualised with 131I scan. In contrast, both MIBI scan and US showed low sensitivity (46.15% and 61.53%, respectively) compared with 131I scan in detecting thyroid remnants. s-Tg was increased in all patients with distant metastases but only in 56% of those with lymph node metastases. Furthermore, s-Tg was increased in 21.42% of patients with thyroid remnants alone (false-positive results). In group 4, MIBI scan was the only examination capable of detecting at an early stage a mediastinal lymph node metastasis in one patient. We conclude that the integrated MIBI scan/neck US protocol: (a) can be proposed as a first-line diagnostic procedure in the follow-up of DTC patients with high s-Tg levels and negative high-dose 131I scan, and (b) may be helpful in the follow-up of DTC patients who undergo partial thyroidectomy alone. Moreover, the combined MIBI scan/neck US/s-Tg protocol appears to be highly sensitive in identifying patients with metastatic disease after total thyroidectomy and prior to 1311 scan; consequently, it may play a prognostic role in distinguishing high-risk from low-risk DTC patients. However, due to the low sensitivity of MIBI scan and neck US in detecting thyroid remnants, this diagnostic approach cannot be used as a predictor of 131I scan results. Lastly, because of the high sensitivity of MIBI scan and neck US in revealing both functioning and non-functioning metastases, this integrated protocol might be helpful in the follow-up of high-risk DTC patients, particularly for the early detection of lymph node metastases in patients with undetectable s-Tg during SHT.     

Comparison of fluorine-18 fluorodeoxyglucose positron emission tomography and technetium-99m methoxyisobutylisonitrile scintimammography in the detection of breast tumours

The aim of this study was to compare, in breast cancer patients, the diagnostic accuracy of positron emission tomography (PET) using fluorine-18 fluorodeoxyglucose (FDG) and scintimammography (SMM) using technetium-99m methoxyisobutylisonitrile (MIBI). A total of 20 patients (40 breasts with 22 lesions) were evaluated serially with MIBI and, on the following day, with FDG. For SMM, planar and single-photon emission tomography imaging in the prone position was performed starting at 10 min following the injection of MIBI (740 MBq). For PET, scans were acquired 45–60 min after the injection of FDG (370 MBq) and attentuation correction was performed following transmission scans. Results from SMM and PET were subsequently compared with the histopathology results. True-positive results were obtained in 12/13 primary breast cancers (mean diameter=29 mm, range 8–53 mm) with both FDG and MIBI. False-negative results were obtained in two local recurrences (diameter <9 mm) with both FDG and MIBI. In benign disease, FDG and MIBI did not localize three fibrocystic lesions, two fibroadenomas and one inflammatory lesion (true-negative), but both localized one fibroadenoma (false-positive). Collectively, the results demonstrate a sensitivity of 92%, and a specificity of 86%, for primary breast cancer regardless of whether FDG or MIBI was used. In contrast to MIBI scintigraphy, FDG PET scored the axillae correctly as either positive (metastatic disease) or negative (no axillary disease) in all 12 patients. The tumour/non-tumour ratio for MIBI was 1.97 (range 1.43–3.1). The mean standard uptake value (SUV) for FDG uptake was 2.57 (range 0.3–6.2). The diagnostic accuracy of SMM was equivalent to that of FDG PET for the detection of primary breast cancer. For the detection of in situ lymph node metastases of the axilla, FDG seems to be more sensitive than^99mTc-MIBI.     

Diagnostic accuracy of fine-needle aspiration versus core-needle biopsy for the diagnosis of thyroid malignancy in a clinical cohort

Objectives

To retrospectively compare the accuracy of fine-needle aspiration (FNA) and core-needle biopsy (CNB) for the diagnosis of thyroid malignancy

Methods

We evaluated the results of FNA and CNB in 555 consecutive thyroid nodules with final diagnoses (malignancy 318, benign 237). All patients underwent FNA and CNB simultaneously for each nodule. We assessed the sensitivity, specificity and accuracy of FNA, CNB and FNA/CNB for the diagnosis of thyroid malignancy.

Results

The sensitivity of FNA, CNB and FNA/CNB for thyroid malignancy was 68.6%, 86.8% and 90.6%, specificity 100%, 99.2% and 99.2%, and accuracy 82.0%, 92.1% and 94.2%, respectively. The sensitivity and accuracy of CNB or FNA/CNB for thyroid malignancy were significantly higher than those of FNA (P?P?Conclusions Our clinical cohort data demonstrated that CNB was more accurate for the diagnosis of thyroid malignancy than FNA, and FNA/CNB was more accurate than CNB alone in small thyroid nodules. CNB will play a complementary role in optimal surgical decision-making and the management of thyroid nodules.

Key Points

? CNB was more accurate for the diagnosis of malignancy than FNA. ? Combined FNA/CNB was more accurate than CNB alone in small thyroid nodules. ? CNB should play at least a complementary role in managing thyroid nodules.     

The benefit of SPECT when added to planar scintigraphy in patients with bone metastases in the spine.

PURPOSE: This study compared the efficiency of SPECT with planar bone scans in differentiating malignant from benign lesions and in detecting metastases to the spine. METHODS: Planar scintigraphy and SPECT were performed in 37 patients with low back pain without known malignancy and in 38 patients with confirmed malignancy. The type, location, and intensity of tracer accumulation were compared on the planar and SPECT scans. The malignant or benign nature of lesions was proved by radiologic methods, histologic findings, 6 month follow-up, or all of these. RESULTS: More metastases were detected by SPECT (SPECT, 58 of 64; planar, 42 of 64; P < 0.01). In three of seven patients with known malignancy who had a normal result of planar scan, only SPECT detected metastases. Fifty-nine metastases were radiologically mainly osteolytic, one was osteoblastic and four were mixed. Most lesions showed increased radioactivity (40 of 42 on planar scans vs. 45 of 58 on SPECT) and 2 of 42 (5%) vs. 12 of 58 (21%) were cold with marginally increased uptake. One of 58 metastases was a cold lesion seen on SPECT only. Lesions were more often malignant than benign when seen on SPECT in a pedicle (n = 5; malignant = 3, benign = 2), in the body and pedicle (n = 22; malignant = 14, benign = 8), within the vertebral body (n = 5; malignant = 4, benign = 1) and in the whole vertebra (n = 6; malignant = 4, benign = 2). The lesion to background ratio was higher on SPECT than on planar scans (SPECT, 2.26; planar scans, 1.86; P < 0.05 in malignant lesions). CONCLUSIONS: SPECT of the spine improved the diagnostic accuracy of bone scans when added to a planar scan in patients with known malignancy and clinical suspicion of spinal metastases when the planar scan was borderline abnormal. It helps in differentiating between benign and malignant lesions of the spine.     

A prospective study of Tc-99m MIBI in the differential diagnosis of pelvic masses in female patients

PURPOSE: This study evaluated the feasibility of Tc-99m MIBI scintigraphy in the differential diagnosis of pelvic masses in female patients before operation. METHODS: Seventy-one patients with pelvic masses were studied with planar imaging over the abdomen and pelvis 5, 15, 30, and 60 minutes after injection of 740 MBq (20 mCi) Tc-99m MIBI. The uptake of the masses was graded, and other abnormal signs, such as intestinal involvement, lymph node involvement, or peritoneal fluid collection, were also considered in image interpretation. An exploratory laparotomy was performed 3 days to 2 weeks after imaging. The scintigraphic diagnosis was compared with that of computed tomography (CT), CA-125 measurement, and pathologic analysis. RESULTS: Forty-one of 46 pelvic masses with no activity were proved benign. Eighteen of 25 with a fixed, focal uptake were malignant. In 19 of 23 masses, intestinal activity noted within 30 minutes was caused by metastases. All three cases with lymph node involvement and six cases with ascites were confirmed malignant. Combining focal uptake with intestinal involvement correctly indicated 22 of 23 malignant conditions before operation, whereas negative scans identified 41 of 48 benign lesions. Four of seven false-positive lesions had a higher cellular component. The diagnostic performance of Tc-99m MIBI is better than that of CT and CA-125 tests, because CT had eight false-positive and three false-negative results, whereas CA-125 had 12 false-positive and 3 false-negative results, respectively. CONCLUSIONS: Tc-99m MIBI is useful for differentiating benign and malignant pelvic masses in female patients. A fixed focal uptake or intestinal uptake of the radiotracer suggests malignancy, with diagnostic sensitivity, specificity, accuracy, and positive and negative predictive values of 95.6%, 85.4%, 88.7%, 75.9%, and 97.6%, respectively, in the current prospective study.     

Optimizing delayed scan time for FDG PET: comparison of the early and late delayed scan

OBJECTIVES: Although dual-time-point scans have been widely used to improve the diagnostic efficacy of FDG PET in differentiating between malignant and benign lesions, no optimized delayed scan time-point has yet been recommended in clinical practice. Our study aimed to explore the most appropriate time for a delayed scan by comparing early and late delayed scans. METHODS: Eighty patients with suspected malignancy were given a three-phase (64 min, 110 min, 233 min after FDG injection) PET/CT scan. The maximum standardized uptake values (SUVs) in the three-phase scans were recorded as SUV1, SUV2 and SUV3, respectively, and compared among three-phase imaging. Retention indices (RIs) of each lesion in two delayed phases were calculated according to the formulae: RI1=SUV2-SUV1/SUV1 x100% and RI2=SUV3-SUV1/SUV1 x100%. RI1 and RI2 in both malignant and benign groups were assessed through correlation analysis. The diagnostic values of two delayed scans were compared through the analysis of the receiver operating characteristic curves. RESULTS: One hundred and nine of 148 lesions were malignant, and 39/148 lesions benign, which were verified by pathological, clinical, laboratory or radiological examination. RI1 and RI2 in malignancy were 14.8+/-13.1% and 10.8+/-20.5% respectively, and the correlation coefficient was 0.6 (P=0.0001). RI1 and RI2 in benign lesions were 11.3+/-28.2% and 9.3+/-42.4%, respectively, and the correlation coefficient was 0.6 (P=0.0001). The area under the ROC curve for RI1 was 0.627+/-0.050 (null hypothesis: true area=0.5, P=0.0130); whereas the area under the ROC curve for RI2 was 0.563+/-0.052 (null hypothesis: true area=0.5, P=0.2321), suggesting that the late delayed scan may have no diagnostic value. CONCLUSION: The retention index values in the two delayed phases have good relativity. The diagnostic value of early delayed imaging is higher than that of late delayed imaging. An early delayed scan, according to our research, should be recommended in clinical practice.     

Three-year clinical experience with VQ SPECT for diagnosing pulmonary embolism: diagnostic performance

Ventilation–perfusion (VQ) single-photon emission computed tomography (SPECT) comprised the administration of SmartVent (n=386) or Technegas (n=1564) and 200 MBq ^99mTc-MAA. 1406 scans were normal, 462 showed PE, 61 showed a singular subsegmental mismatched defect, 21 scans were non-diagnostic. 26% of scans performed with Technegas showed PE, compared to 15% with SmartVent. VQ SPECT had a sensitivity of 95.7%, specificity 98.6%, positive predictive value 95.7%, negative predictive value 98.6%. A normal VQ SPECT scan implied a more than ten-fold lower cause-specific mortality (1 in 1406) than a scan showing PE (1 in 116). NPV of a negative D-dimer was 94.3%.     

99Tcm-MIBI甲状腺显像鉴别甲状腺结节良恶性再认识

目的评价^99Tc^m-甲氧基异丁基异腈（MIBI）甲状腺亲肿瘤显像鉴别甲状腺结节良恶性的临床价值。方法106例甲状腺结节手术患者中101例先进行了甲状腺结节常^99Tc^mO4^-显像；106例患者均静脉注射^99Tc^m-MIBI 370 MBq后进行15min早期和2h延迟显像，结果与病理检查结果对比。结果13例甲状腺恶性肿瘤中的5例、93例良性结节中的23例^99Tc^m-MIBI显像阳性。^99Tc^m-MIBI显像诊断甲状腺恶性肿瘤的灵敏度为38．5％，特异性为75．3％，准确性为70．8％。甲状腺良恶性肿瘤显像的阳性率差异无显著性（x^2=0．49，P〉0．05）。结论^99Tc^m-MIBI显像不能鉴别甲状腺结节的良恶性，其临床意义有限。     

Effects of fine-needle aspiration on the US appearance of the breast.

Fine-needle aspiration (FNA) of normal breast tissue or benign lesions can cause changes that suggest malignancy at ultrasound (US) examination. Serial US studies showed that three of 17 patients developed signs mimicking malignancy following FNA of palpable breast lumps. A second group of 14 patients had US signs of malignancy in palpable lumps following recent FNA. Nine patients with benign lesions were unnecessarily worried, since the appearance was probably due to FNA. Diagnosis of malignancy was delayed in one of five patients because the US appearance was attributed to the FNA in the presence of false-negative cytologic findings. FNA of normal breast tissue or benign masses produced tissue changes in 18% of cases that altered the US appearance from normal or benign to possibly malignant. The changes took up to 4 months to subside. If US is clinically indicated, it should be performed before FNA.     

The value of CT scanning and percutaneous fine needle aspiration of adrenal masses in biopsy-proven lung cancer.

Pre-operative CT scans of 546 patients with biopsy-proven primary bronchial carcinoma were reviewed. Twenty-two patients had a solid adrenal tumour (2 bilateral). Sixteen underwent percutaneous fine needle aspiration (FNA). Malignant cells were aspirated in five, eight revealed benign cells and in three cases there was insufficient material for diagnostic purposes. Six patients did not undergo FNA, four of these were considered to have benign adenomas on CT. This was confirmed by the unchanged CT image at more than 21 months follow-up. The five subjects with FNA-proven metastases died at a median of 14 months (range 3-24 months). All five would have been regarded as operable on their staging chest CT scan. Five patients with a negative biopsy underwent surgery, two died of metastases at 6 and 11 months respectively and one died of post-operative complications. The other two have unchanged adrenal lesions on CT at 9 months and 25 months. The CT appearances of these lesions were analysed. Well defined, low attenuation lesions which had a smooth attenuation rim or only involved part of the gland were benign and the survivors had unchanged CT appearances at follow-up (six lesions in five patients). Of these four lesions were less than or equal to 2 cm in diameter. Low attenuation lesions without a rim were malignant (n = 2). These latter both measured more than 2 cm in diameter. The CT appearances of many adrenal lesions were insufficiently distinctive to exclude malignancy and biopsy was necessary to establish a diagnosis.