Primary Hyperparathyroidism Patients with Positive Preoperative Sestamibi Scan and Negative Ultrasound Are More Likely to Have Posteriorly Located Upper Gland Adenomas (PLUGs)

Background

Standard preoperative imaging for primary hyperparathyroidism usually includes sestamibi scanning (MIBI) and ultrasound (US). In a subset of patients with a positive MIBI and a negative US, we hypothesize that the parathyroid adenomas are more likely to be located posteriorly in the neck, where anatomically they are more difficult to detect by US.

Methods

We retrospectively reviewed the records of 661 patients treated for primary hyperparathyroidism between 2004 and 2009 at a tertiary referral center. We included patients who for their first operation had a MIBI that localized a single lesion in the neck and an US that found no parathyroid adenoma. We excluded patients with persistent or recurrent hyperparathyroidism, and patients with MIBIs that were negative, that had more than one positive focus, or that had foci outside of the neck. Sixty-six cases were included in the final analysis.

Results

A total of 54 patients (83%) had a single adenoma, 4 (6%) had double adenomas, and 7 (11%) had hyperplasia. Thirty-three patients (51%) had a single upper gland adenoma; 19 of these (58%) were posteriorly located upper gland adenomas (PLUGs). PLUGs occurred more often on the right side than on the left (P = 0.048, Fisher’s test). PLUGs were also larger than other single adenomas (mean 1.85 vs. 1.48 cm, P = 0.021, t-test). Seventy-six percent of patients successfully underwent a unilateral or focused exploration. Six patients (9%) had persistent disease, which is double our group’s overall average (4–5%).

Conclusions

Primary hyperparathyroid patients with preoperative positive MIBI and negative US are more likely to have PLUGs.     

Sestamibi Imaging for Primary Hyperparathyroidism: The Impact of Surgeon Interpretation and Radiologist Volume

Background

Preoperative localization is the first step towards minimally invasive targeted parathyroidectomy. While there are data emphasizing that surgeon experience optimizes operative outcomes, the role of the radiologist??s experience in successful preoperative imaging is unclear. We hypothesized that the accuracy of sestamibi scanning for primary hyperparathyroidism is dependent upon surgeon interpretation and radiologist volume.

Methods

Between January 2000 to August 2009, 1,255 patients underwent parathyroidectomy for hyperparathyroidism at our institution. Of these, 763 had sestamibi scans for primary hyperparathyroidism. All scans were reviewed by surgeons and radiologists blinded, and were correlated with the operative findings and pathological reports. Radiologists were grouped into high volume (>50 cases/year, HV-RAD) or low volume (<50 cases/year, LV-RAD) based upon a database of >6,000 parathyroid cases reported by 89 regional hospitals.

Results

Of the 763 patients, 77?% were female and the mean age was 60?years. Mean baseline calcium and parathyroid hormone levels were 11.2?±?0.03?mg/dl and 133?±?3.27?pg/ml, respectively. The sensitivity of the surgeon (93?%) was higher than both HV (83?%) and LV (72?%) radiologists. Importantly, the positive predictive values were similar: 96?% for surgeon, 93?% for HV-RAD, and 98?% for LV-RAD. As a result, out of 99 scans which were correctly read by the surgeon but not by radiologist, 84 were read as negative by radiologist, 11 on the wrong side of the neck, and 4 on the same side but the wrong gland.

Conclusions

Surgeon interpretation and radiologist volume increase the likelihood of successful preoperative sestamibi parathyroid localization for primary hyperparathyroidism. We recommend that imaging be reviewed by experienced parathyroid surgeons rather than relying on radiological interpretation alone.     

Surgeon-Performed Ultrasound for Preoperative Localization of Abnormal Parathyroid Glands in Patients with Primary Hyperparathyroidism

Background The introduction of portable ultrasound equipment enables surgeons to perform ultrasound examinations in a clinic setting. This study was undertaken to evaluate surgeon-performed ultrasound (SP-US) in patients with primary hyperparathyroidism (PHPT). Methods Between July 2003 and March 2004, 65 patients with PHPT were evaluated with SP-US and 48 of these patients underwent parathyroid surgery. Among this group of 48 evaluable patients, 47 had preoperative imaging with technetium-99m sestamibi scanning (MIBI), and 12 had an additional ultrasound examination at an external radiology department (RP-US). Results All patients were cured of PHPT and the operative findings were used to determine the true status of the parathyroid glands of each patient. Twenty-four (50%) patients had concomitant thyroid nodules which were identified by SP-US, and 4 (8.3%) patients had simultaneous thyroid operations, 2 of which were for thyroid cancer. Considering data for all patients, SP-US had significantly higher sensitivity than MIBI or RP-US (60% vs. 46%, P = 0.013, and 60% vs. 11%, P = 0.004 respectively). Among the patients with a single adenoma, SP-US, MIBI, and RP-US had sensitivities of 83%, 63%, and 13% respectively. The specificities of all three imaging techniques were uniformly high and were not significantly different from each other. Conclusions Surgeon-performed ultrasound is an accurate modality for localizing abnormal parathyroid glands in patients with PHPT, with results that compare favorably with other parathyroid imaging modalities.     

Selective Parathyroid Hormone Venous Sampling in Patients with Persistent or Recurrent Primary Hyperparathyroidism and Negative,Equivocal or Discordant Noninvasive Imaging

Background

In patients with persistent (P-PHPT) or recurrent (R-PHPT) primary hyperparathyroidism, preoperative localization is important. Selective parathyroid hormone venous sampling (sPVS) is an invasive technique that can be used to regionalize and/or lateralize the source of PHPT when noninvasive imaging studies are nonlocalizing. The aim of the present study was to assess the role of sPVS in the preoperative evaluation of patients with P-PHPT or R-PHPT and negative, equivocal, or discordant noninvasive imaging localization.

Methods

After IRB-approval a retrospective review of all patients with P-PHPT or R-PHPT and nonlocalizing noninvasive imaging that underwent sPVS from 2000 to 2014 was performed. The location of the source of PHPT at sPVS was predicted by a parathyroid hormone (PTH) gradient and compared to the surgical, pathology, and biochemical follow-up data as the gold standard. Sensitivity and positive predictive value (PPV) were calculated.

Results

Of 30 patients who underwent sPVS, 12 patients did not undergo surgical exploration due to negative or non-localizing PTH gradient (n = 8) or opted for medical management (n = 4). Of the 18 patients who underwent surgical exploration, 17 (94 %) had a positive PTH gradient and pathologic parathyroid tissue identified at surgery. Sensitivity and PPV of sPVS were 93 and 77 %, respectively, for all surgical cases, 86 and 60.0 % for cervical cases (n = 11), and 100 and 100 % for mediastinal cases (n = 7). Sixteen patients (89 %) were surgically cured.

Conclusions

In patients with P-PHPT or R-PHPT and nonlocalizing imaging studies, sPVS is a sensitive test for localizing the source of PHPT when a positive PTH gradient is present.

     

Video-Assisted Bilateral Neck Exploration in Patients with Primary Hyperparathyroidism and Failed Localization Studies

Background  

In primary hyperparathyroidism (pHPT) positive preoperative localization studies are accepted as a precondition for applying minimally invasive surgical techniques. Without localization, open bilateral neck exploration (BNE) is considered the standard option. Thepresent study analyzes the feasibility and effectiveness of minimally invasive video-assisted BNE in patients with pHPT and negative or discordant localization studies.     

Quantitative Ultrasound and Bone Mineral Density in Patients with Primary Hyperparathyroidism Before and after Surgical Treatment

The aim of this study was to assess the pattern of ultrasound (QUS) parameters and bone mineral density at different skeletal sites in patients with primary hyperparathyroidism (PHPT) before and after surgical treatment. In 22 patients (age range 28–74 years) with PHPT we measured speed of sound (SOS), attenuation (BUA) and Stiffness at the calcaneus, amplitude-dependent speed of sound (AD-SoS) at proximal phalanges, and bone mineral density at lumbar spine (BMD-LS) and at the mid-radius (BMD-MR) and ultradistal radius (BMD-UDR) before, 1 and 2 years after surgical operation. Twenty-two age- and sex-matched healthy subjects provided control data. Before surgery, all parameters apart from SOS were significantly lower in PHPT patients than in controls. At the end of the study period, BMD-LS increased by 7.0%, BMD-UDR by 7.4% and BMD-MR by 11.0%. The changes in ultrasound parameters after surgery were lower (0.44% for SOS, 2.2% for BUA, 3.3% for Stiffness and 2.6% for AD-SoS); however, the increase was statistically significant (p<0.05 and p<0.01, respectively) only for Stiffness and AD-SoS. Our results indicate that parathyroidectomy increases both axial and appendicular BMD and influences QUS parameters differently at the calcaneus and at the phalanges. The combined use of BMD and QUS could improve the assessment of skeletal status in patients with PHPT before and after surgery. Received: 22 January 1999 / Accepted: 25 August 1999     

A Meta-analysis of Preoperative Localization Techniques for Patients with Primary Hyperparathyroidism

Background  

Reported accuracy of preoperative localization imaging for primary hyperparathyroidism (pHPT) varies. The purpose of this study is to determine the accuracy of ultrasound, sestamibi-single photon emission computed tomography (SPECT), and four-dimensional computed tomography (4D-CT) as preoperative localization strategies.     

Inframanubrial Parathyroid Glands in Patients with Primary Hyperparathyroidism: Alternatives to Sternotomy

Deep inframanubrial parathyroid tumors have traditionally been excised through a median sternotomy. With the advent of minimally invasive surgical access, we chose to examine the treatment options and outcomes of patients with inframanubrial mediastinal parathyroid tumors. Patients with primary hyperparathyroidism seen at a university medical center over a 12-year period were retrospectively reviewed. The utility of localization studies, methods of treatment, complications, and outcomes were examined in patients with a parathyroid tumor located in the mediastinum inferior to the manubrium. Patients with parathyroid adenomas located at the thoracic inlet were excluded. Sixteen patients with inframanubrial mediastinal tumors were treated during the study period. Altogether, 81% of the patients had undergone at least one prior neck exploration for primary hyperparathyroidism. Preoperative calcium and parathyroid hormone levels were 12.4 ± 0.36 mg/dl and 273 ± 70 pg/ml, respectively. Localization studies identified mediastinal parathyroid adenomas in the following locations: anterior mediastinum (n = 8), middle mediastinum (n = 7), posterior mediastinum (n = 1). Mediastinal computed tomography and technetium-sestamibi scans demonstrated the best sensitivity, 92% and 85%, respectively. Seven patients underwent successful excision of the mediastinal adenoma by transcervical mediastinal exploration with the Cooper retractor. The other patients underwent angiographic ablation (n = 4), anterior mediastinotomy (n = 3), video-assisted thoracoscopy (VATS) (n = 1), and VATS plus thoracotomy (n = 1). The mean hospital stay for the study group was 2.9 ± 0.7 days. The complication rate was 25%. All patients were normocalcemic after a mean follow-up of 15 ± 7 months. Most inframanubrial mediastinal parathyroid tumors can be successfully managed without median sternotomy.     

Initial Surgery for Benign Primary Hyperparathyroidism: An Analysis of 1,300 Patients in a Teaching Hospital

Background

Success rates of initial surgery for primary hyperparathyroidism (pHPT) are greater than 95 % in specialized centers, mostly referring to single-surgeon experiences. The present study was performed to identify changes in clinical manifestations, diagnostic procedures, surgical strategies, and outcome of initial parathyroid interventions in a teaching hospital during the past 25 years with special regard to the surgical expertise.

Methods

Clinical data of patients who underwent an initial neck exploration for benign pHPT between 1985 and 2010 at the University hospital Marburg were retrospectively evaluated. All data were analyzed particularly with regard to the implementation of additional pre- and intraoperative procedures and to the particular surgical strategy. In addition, operative results were furthermore analyzed with regard to the experience of the responsible surgeons.

Results

An initial neck exploration for benign pHPT was performed in 1,300 patients. Of these, 1,035 patients had a bilateral cervical exploration (BCE) and 265 patients had a focused, minimally invasive parathyroidectomy (MIP). Cure rates did not differ between focused surgeries and BCE (98.9 vs. 98.3 %, p = 0.596) after a mean follow-up of 33.4 (± 44.3) months. Postoperative transient hypoparathyroidism was significantly lower in the MIP group (11 vs. 47 %, p < 0.0001). The rate of permanent recurrent laryngeal nerve palsies (0.4 vs. 2 %, p = 0.064) and nonsurgical complications (0 vs. 1.4 %, p = 0.0875) tended to be lower in the MIP group. Success and complication rates of chief surgeons (n = 2), attending surgeons (n = 20), and residents (56 < 3 years, 30 > 3 years) were similar, despite a significantly shorter operating time in the chief surgeon group (p < 0.01).

Conclusions

Despite the implementation of several diagnostic procedures and significant changes concerning the surgical strategy, high success rates of primary interventions for pHPT did not change over the past three decades. High success rates also can be achieved in a teaching hospital, provided that surgery is supervised by an experienced endocrine surgeon. MIP is the treatment of choice in patients with benign sporadic pHPT and positive preoperative localization studies.     

Outcomes of Parathyroidectomy in Patients with Primary Hyperparathyroidism: A Systematic Review and Meta-analysis

Background

Parathyroidectomy is a definitive treatment for primary hyperparathyroidism. Patients contemplating this intervention will benefit from knowledge regarding the expected outcomes and potential risks of the currently available surgical options.

Purpose

To appraise and summarize the available evidence regarding benefits and harms of minimally invasive parathyroidectomy (MIP) and bilateral neck exploration (BNE).

Data sources

A comprehensive search of multiple databases (MEDLINE, EMBASE, and Scopus) from each database’s inception to September 2014 was performed.

Study selection

Eligible studies evaluated patients with primary hyperparathyroidism undergoing MIP or BNE.

Data extraction

Reviewers working independently and in duplicate extracted data and assessed the risk of bias.

Data synthesis

We identified 82 observational studies and 6 randomized trials at moderate risk of bias. Most of them reported outcomes after MIP (n = 71). Using random-effects models to pool results across studies, the cure rate was 98 % (95 % CI 97–98 %, I ² = 10 %) with BNE and 97 % (95 % CI 96–98 %, I ² = 86 %) with MIP. Hypocalcemia occurred in 14 % (95 % CI 10–17 % I ² = 93 %) of the BNE cases and in 2.3 % (95 % CI 1.6–3.1 %, I ² = 87 %) with MIP (P < 0.001). There was a statistically significant lower risk of laryngeal nerve injury with MIP (0.3 %) than with BNE (0.9 %), but similar risk of infection (0.5 vs. 0.5 %) and mortality (0.1 vs. 0.5 %).

Limitations

The available evidence, mostly observational, is at moderate risk of bias, and limited by indirect comparisons and inconsistency for some outcomes (cure rate, hypocalcemia).

Conclusion

MIP and BNE are both effective surgical techniques for the treatment of primary hyperparathyroidism. The safety profile of MIP appears superior to BNE (lower rate of hypocalcemia and recurrent laryngeal nerve injury).

     

The Outcome of Cervical Exploration for Asymptomatic and Symptomatic Patients with Primary Hyperparathyroidism

This study examined the success and safety of cervical exploration in patients with primary hyperparathyroidism (HPT). The presentation, pathologic findings, and outcome of patients with asymptomatic primary HPT were compared with those with symptomatic disease. Records of patients undergoing cervical exploration for primary HPT from January 1993 until December 31, 2003, were reviewed. Information collected consisted of preoperative symptoms, calcium and parathormone (PTH) levels, imaging studies, operative findings, pathology, and outcome of the patients. The groups with asymptomatic and symptomatic primary HPT were compared. In all, 139 patients were studied; 31 (22.3%) were asymptomatic (group I), and 108 (77.7%) had symptoms (group II). The two groups were also comparable regarding mean age, sex, and the yield of the imaging studies. The mean preoperative serum calcium level was comparable in the two groups (11.1mg/dl versus 11.3 mg/dl). However, PTH levels were significantly lower in group I than in group II (142 pg/dl versus 283 pg/dl, P = 0.01). The weight of the adenoma was also significantly less in group I than in group II (1082 mg versus 1679 mg P = 0.079). The outcome of the surgical exploration was comparable in the two groups with an immediate success rate close to 98% and a long-term success rate of 95.4%. Cervical exploration and parathyroidectomy in patients with primary HPT is a safe procedure with a high success rate and favorable outcome.     

Long-Term Effects of Neridronate and its Discontinuation in Patients with Primary Hyperparathyroidism

In patients with primary hyperparathyroidism (PHPT) not suitable for surgical correction, a skeletal protection with bisphosphonates is considered a reasonable option, but the long-term effects after treatment discontinuation are not well known. Sixty postmenopausal women with PHPT were given 400–600 IU vitamin D₃ daily and 100 mg neridronate IV every 2 months for 2 years with 2 additional years of follow-up without antiresorptive therapies. Bone mineral density (BMD) progressively rose by 6.7 ± 7.6% (SD) and by 2.9 ± 4.5% at the spine and femoral neck, respectively. During follow-up, mean BMD progressively fell, but after 2 years it was still 3.9 ± 5.5% higher than baseline values at the spine. Bone alkaline phosphatase and serum C-telopeptide of type I collagen decreased significantly within 6 months (28 and 49% versus baseline, respectively) and rose to baseline values within 6–12 months during follow-up. Serum PTH significantly rose from baseline during treatment, but it remained significantly higher than baseline during follow-up. The PTH changes were significantly correlated with serum 25-hydroxyvitamin D (25OHD) levels. In conclusion, in this study we observed that in patients with mild PHPT treatment with bisphosphonates is associated with the expected changes in bone-turnover markers and that the significant increases of both hip and spine BMD are partially maintained for at least 2 years after treatment discontinuation at the vertebral site. The marked increases in serum PTH levels, particularly in subjects with low 25OHD levels, persist after treatment discontinuation and this raises the suspicion that this might reflect a worsening of PHPT.     

136例原发性甲状旁腺功能亢进的诊治体会

目的分析原发性甲状旁腺功能亢进症的临床特点、诊断和治疗方法。方法回顾性分析四川大学华西医院2004年1月至2012年12月期间初次手术治疗且资料完整的原发性甲状旁腺功能亢进患者的临床资料。结果136例甲状旁腺功能亢进患者中骨型52例（38,23％）,肾型17例（12．50％）,骨。肾型7例（5．15％）,生化型24例（17．65％）,合并其他临床表现者36例（26．47％）。术前甲状旁腺激素（parathyroid hormone,PTH）值为（106．20±88．88）pmol／L（6．91～390pmol／L）,血钙值为（3．12±0．66）mmol／L（2．15～5．77mmol／L）。甲状腺及颈部淋巴结彩超和锝．甲氧基异丁基异腈放射性核素双时相显像（99Tcm-MIBI）定位诊断与手术发现符合率分别为75．00％及85．29％,联合CT检查三者符合率为86．76％。术后病理诊断：良性病变129例（94．85％）,甲状旁腺癌7例（5．15％）。良性病变中甲状旁腺腺瘤119例（92．25％）,其中单发114例（95．80％）,多发腺瘤或甲状旁腺瘤合并甲状旁腺增生5例（4．20％）;甲状旁腺增生10例（7．75％）,其中8例为甲状旁腺不典型增生或增生活跃。124例（91．18％）患者术后3d内PTH降至正常上限以下。124例（91．18％）获随访,随访时间6～112个月,中位随访时间49个月;12例（8．82％）失访。术后6个月有2例（1．47％）甲状旁腺癌患者肿瘤复发,其余病例无复发。3例（2．21％）甲状旁腺癌患者分别于术后18,19及23个月死亡,其中2例死于甲状旁腺癌全身转移,1例死于心血管意外。结论原发性甲状旁腺功能亢进的临床表现多样,手术是治疗原发性甲状旁腺功能亢进的有效手段。     

Arterial Microcalcification in Atherosclerotic Patients with and Without Chronic Kidney Disease: A Comparative High-Resolution Scanning X-Ray Diffraction Analysis

Vascular calcification, albeit heterogeneous in terms of biological and physicochemical properties, has been associated with ageing, lifestyle, diabetes, and chronic kidney disease (CKD). It is unknown whether or not moderately impaired renal function (CKD stages 2-4) affects the physiochemical composition and/or the formation of magnesium-containing tricalcium phosphate ([Ca,Mg](3)[PO(4)](2), whitlockite) in arterial microcalcification. Therefore, a high-resolution scanning X-ray diffraction analysis (European Synchrotron Radiation Facility, Grenoble, France) utilizing histological sections of paraffin-embedded arterial specimens derived from atherosclerotic patients with normal renal function (n = 15) and CKD (stages 2-4, n = 13) was performed. This approach allowed us to spatially assess the contribution of calcium phosphate (apatite) and whitlockite to arterial microcalcification. Per group, the number of samples (13 vs. 12) with sufficient signal intensity and total lengths of regions (201 vs. 232 μm) giving rise to diffractograms ("informative regions") were comparable. Summarizing all informative regions per group into one composite sample revealed calcium phosphate/apatite as the leading mineral phase in CKD patients, whereas in patients with normal renal function the relative contribution of whitlockite and calcium phosphate/apatite was on the same order of magnitude (CKD, calcium phosphate/apatite 157 μm, whitlockite 38.7 μm; non-CKD, calcium phosphate/apatite 79.0 μm, whitlockite 94.1 μm; each p < 0.05). Our results, although based on a limited number of samples, indicate that chronic impairment of renal function affects local magnesium homeostasis and thus contributes to the physicochemical composition of microcalcification in atherosclerotic patients.     

Biochemical Effects from Treatment with Bisphosphonate and Surgery in Patients with Primary Hyperparathyroidism

Patients with primary hyperparathyroidism (pHPT) are sometimes treated with bisphosphonates (BPs) as an alternative to surgery despite sparse documentation of the efficacy in this disorder. It is therefore of interest to study the biochemical effects from BPs in patients with pHPT. A series of 21 pHPT patients with serum calcium levels > 2.8 mmol/L were included. One month before surgery the patients underwent intravenous infusions of 30 to 40 mg pamidronate. Study parameters were total and ionized serum calcium, intact parathormone (PTH), alkaline phosphatase (ALP) and isoenzymes, creatinine, osteocalcin, 25-OH vitamin D₃, 1,25-OH₂ vitamin D₃, urine calcium/creatinine, and osmolality. Registration of hypercalcemia-related symptoms were done by questionnaire. After pamidronate there was a temporary reduction in serum calcium with a nadir at 6 to 10 days. Normalization of serum calcium was achieved only by surgery. Intact PTH rose after pamidronate, with a maximum on day 6. Urinary calcium excretion was reduced after both pamidronate and surgery. ALP was reduced 30 days after pamidronate and also after surgery. Serum osteocalcin was not influenced by pamidronate. No statistically significant differences in symptoms were reported after treatment. In conclusion, there was a short, limited calcium-lowering effect from pamidronate in pHPT patients and a transient increase in PTH corresponding to the reduced calcium concentration. An obvious change in bone markers was found only after surgery. Treatment with BPs should not be considered an alternative to surgery, which is still the only method to cure patients with pHPT.This article was presented at the International Association of Endocrine Surgeons meeting, Uppsala, Sweden June 14–17, 2004.     

Graphic Trace Analysis of Ultrasound at the Phalanges May Differentiate Between Subjects with Primary Hyperparathyroidism and with Osteoporosis: A Pilot Study

Bone loss characterizes both primary hyperparathyroidism (PHPT) and osteoporosis (OP) but with a different histologic pattern, and this could partially explain the different fracture incidence in these two populations. Quantitative ultrasound (QUS), influenced by bone structural parameters other than bone mineral density (BMD), could evidence these differences, opening new perspectives in the evaluation of patients with metabolic bone diseases. The aim of the present study was to investigate the usefulness of QUS graphic trace parameters, assessed at the phalanx, in discriminating between PHPT bone disease and osteoporosis. We studied 34 patients with PHPT (mean age 59.7 ± 12.7 years), 35 patients with OP (mean age 60.6 ± 7.1 years) and 34 healthy subjects as controls (mean age 59.1 ± 9.4 years). In all subjects QUS measurements were performed at the phalanx with a Bone Profiler (IGEA, Italy), obtaining the amplitude-dependent speed of sound (AD-SoS), fast wave amplitude (FWA), signal dynamic (SDy), bone transmission time (BTT) and ultrasound bone profile index (UBPI). Moreover, serum calcium, phosphorus, parathyroid hormone (PTH), bone isoenzyme of alkaline phosphatase (B-ALP) and ionized calcium were measured in all subjects in the morning under fasting conditions. In PHPT patients BTT was correlated with PTH, ionized calcium and B-ALP levels (r=–0.47, –0.57 and –0.44, respectively; p <0.01), whereas FWA, SDy and UBPI correlated only with B-ALP (r=–0.43, –0.46 and –0.50, respectively; p <0.01). Moreover, FWA, SDY and UBPI were significantly (p<0.01) lower and BTT significantly (p<0.001) higher in OP than in PHPT patients. UBPI, BTT, FWA and the BTT/FWA ratio, but not SDy, were able to discriminate between the two groups (area under the curve =0.66, 0.69, 0.67 and 0.81, respectively).  Our findings show that ultrasound signal parameters are differently influenced by bone changes characterizing primary hyperparathyroidism or osteoporosis. This suggests that the QUS signal could be a useful instrument in discriminating and studying some of the bone alterations typical of metabolic bone diseases. Received: 15 February 2001 / Accepted: 27 August 2001