Musculoskeletal Imaging with Computed Tomography and Magnetic Resonance Imaging: When is Computed Tomography the Study of Choice?

Indications for computed tomography (CT) of the musculoskeletal system, especially with the advent of 16-slice multidetector CT (MDCT), are numerous. In addition to the evaluation of the trauma patient where CT is essential when imaging complex skeletal injuries, MDCT is particularly useful in patients who have had prior surgery. In postoperative cases, metal artifact typically prohibits magnetic resonance imaging evaluation, but volume-rendering of a MDCT axial database virtually eliminates streak artifact associated with hardware. For the evaluation of masses, CT provides the ability to detect and characterize calcification, cortical disruption, and periosteal reaction. In this article, these and other indications for performance of CT of the musculoskeletal system will be discussed.     

The Journal of Cardiovascular Computed Tomography year in review – 2019

The purpose of this review is to summarize the work published by the Journal of Cardiovascular Computed Tomography (JCCT) for the year 2019, highlighting original research and new guidelines.     

Value of Computed Tomography–guided Core Needle Biopsy in Diagnosis of Primary Pulmonary Lymphomas

PurposeTo evaluate the value of computed tomography (CT)–guided core needle biopsy in diagnosis of primary pulmonary lymphoma and its subtypes.Materials and MethodsA retrospective analysis of the records of all patients with primary pulmonary lymphoma between January 2005 and August 2011 was performed. There were 25 patients referred to the radiology department for CT-guided core needle biopsy. The success rate and complications were assessed.ResultsA definitive diagnosis and accurate histologic subtype were obtained in 21 patients with a success rate of 84.0%. Diagnosis was made in the other four patients with bronchoscopy and surgery. Non-Hodgkin lymphoma (NHL) was the diagnosis in all patients. Most subtypes were mucosa-associated lymphoid tissue (MALT) lymphomas (n = 19). The remaining subtypes included three diffuse large B-cell NHLs, two peripheral T-cell lymphomas not otherwise specified, and one anaplastic large cell NHL. The success rate of core needle biopsy was 95% (18 of 19) for MALT lymphomas, 67% (2 of 3) for diffuse large B cell NHLs, and 33% (1 of 3) for other NHLs. The success rate for MALT lymphomas was significantly higher than that of non-MALT lymphomas according to Fisher exact t test (P = .031). No serious complications occurred in any patients.ConclusionsCT-guided core needle biopsy is a reliable procedure to assist in diagnosis and classification of primary pulmonary lymphomas, especially MALT lymphomas.     

Quantitative Single-Photon Emission Computed Tomography/Computed Tomography for Evaluation of Salivary Gland Dysfunction in Sjögren’s Syndrome Patients

Purpose

The purpose of the study was to investigate the usefulness of quantitative salivary single-photon emission computed tomography/computed tomography (SPECT/CT) using Tc-99m pertechnetate in Sjögren’s syndrome (SS).

Methods

We retrospectively reviewed quantitative salivary SPECT/CT data from 95 xerostomic patients who were classified as either SS (n?=?47, male:female?=?0:47, age?=?54.60?±?13.16 y [mean?±?SD]) or non-SS (n?=?48, male:female?=?5:43, age?=?54.94?±?14.04 y) by combination of anti-SSA/Ro antibody, labial salivary gland biopsy, unstimulated whole saliva flow rate, and Schirmer’s test. Thyroid cancer patients (n?=?43, male:female?=?19:24, age?=?46.37?±?12.13 y) before radioactive iodine therapy served as negative controls. Quantitative SPECT/CT was performed pre-stimulatory 20 min and post-stimulatory 40 min after injection of Tc-99m pertechnetate (15 mCi). The %injected dose at 20 min and the %excretion between 20 and 40 min were calculated for parotid and submandibular glands, generating four quantitative parameters: %parotid uptake (%PU), %submandibular uptake (%SU), %parotid excretion (%PE), and %submandibular excretion (%SE). The most useful parameter for SS diagnosis was investigated.

Results

The uptake parameters (%PU and %SU) were significantly different among the SS, non-SS, and negative controls (p?=?0.005 for %PU and p?<?0.001 for %SU, respectively), but the excretion parameters (%PE and %SE) were not (p?>?0.05 for both). The %PU and %SU were significantly lower in SS than in the negative controls and non-SS (p?<?0.05 for all pair-wise comparisons). Additionally, the %SU was significantly lower in non-SS than in the negative controls (p?<?0.05). Receiver-operating characteristic analysis revealed that the %SU had the greatest area-under-the curve of 0.720 (95% confidence interval?=?0.618–0.807). Using the optimal cut-off value of %SU?≤?0.07%, SS was identified with a sensitivity of 70.21% and a specificity of 70.83%.

Conclusion

Reduced submandibular uptake of Tc-99m pertechnetate at 20 min (%SU) was proved useful for the diagnosis of SS. Quantitative salivary gland SPECT/CT holds promise as an objective imaging modality for assessment of salivary dysfunction and may facilitate accurate classification of SS.

     

Frequency and Risk Factors of Various Complications After Computed Tomography–Guided Radiofrequency Ablation of Lung Tumors

Objective To retrospectively determine the frequency and risk factors of various side effects and complications after percutaneous computed tomography–guided radiofrequency (RF) ablation of lung tumors. Methods We reviewed and analyzed records of 112 treatment sessions in 57 of our patients (45 men and 12 women) with unresectable lung tumors treated by ablation. Risk factors, including sex, age, tumor diameter, tumor location, history of surgery, presence of pulmonary emphysema, electrode gauge, array diameter, patient position, maximum power output, ablation time, and minimum impedance during ablation, were analyzed using univariate and multivariate analyses. Results Total rates of side effects and minor and major complications occurred in 17%, 50%, and 8% of treatment sessions, respectively. Side effects, including pain during ablation (46% of sessions) and pleural effusion (13% of sessions), occurred with RF ablation. Minor complications, including pneumothorax not requiring chest tube drainage (30% of sessions), subcutaneous emphysema (16% of sessions), and hemoptysis (9% of sessions) also occurred after the procedure. Regarding major complications, three patients developed fever >38.5°C; three patients developed abscesses; two patients developed pneumothorax requiring chest tube insertion; and one patient had air embolism and was discharged without neurologic deficit. Univariate and multivariate analyses suggested that a lesion located ≤1 cm of the chest wall was significantly related to pain (p < 0.01, hazard index 5.76). Risk factors for pneumothorax increased significantly with previous pulmonary surgery (p < 0.05, hazard index 6.1) and presence of emphysema (p <0.01, hazard index 13.6). Conclusion The total complication rate for all treatment sessions was 58%, and 25% of patients did not have any complications after RF ablation. Although major complications can occur, RF ablation of lung tumors can be considered a safe and minimally invasive procedure.     

Repeatability of Computerized Tomography–Based Anthropomorphic Measurements of Frailty in Patients With Pulmonary Fibrosis Undergoing Lung Transplantation

Purpose

To determine interreader and intrareader repeatability and correlations among measurements of computerized tomography–based anthropomorphic measurements in patients with pulmonary fibrosis undergoing lung transplantation.

Impact of F-18 Fluorodeoxyglucose Positron Emission Tomography–Computed Tomography on Oncologic Patient Management: First 2 Years' Experience at a Single Canadian Cancer Center

Purpose

The purpose of this study was to assess the influence of positron emission tomography–computed tomography (PET-CT) results on patient management from a single Canadian oncology center during its first 2 years of operation.

Methods

A total of 3,779 consecutive patients, 18 years of age and older, who were referred for PET-CT imaging at the British Columbia Cancer Agency between July 1, 2005 and June 30, 2007, were included in this analysis. Results were tabulated from a standard questionnaire, which was given to referring physicians following completion of their patient's PET-CT study.

Results

From July 1, 2005 to June 30, 2007, 3,779 consecutive fluoro-2-deoxyglucose PET-CT examinations were performed in patients aged 18 years or older. A total of 3,429 referring-physician surveys (90.7%) were returned. The results of the PET-CT study resulted in a change in treatment decision in 49.8% of the studies and resulted in improved decision making in 83.2% of the studies.

Conclusion

This series demonstrated that the results from PET-CT studies performed at a single Canadian oncology center during the first 2 years of its operation altered patient management in 50% of cases and resulted in improved decision making in the majority of cases.     

Prognostic Value of 18F-Fluorodeoxyglucose Positron Emission Tomography–Computed Tomography in Predicting Survival in Patients with Unresectable Metastatic Melanoma to the Liver Undergoing Yttrium-90 Radioembolization

PurposeTo investigate the prognostic value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography–computed tomography (PET-CT) in predicting survival in patients with unresectable metastatic melanoma to the liver undergoing yttrium-90 (⁹⁰Y) radioembolization.Materials and MethodsA retrospective review of 12 patients with unresectable hepatic melanoma metastases (5 patients with cutaneous metastases, 7 patients with ocular metastases) who underwent ¹⁸F-FDG PET-CT before ⁹⁰Y was performed. Metabolically significant tumors, defined as having a long-axis diameter ≥ 1 cm and maximum standardized uptake value (SUV_max) ≥ 2.5, were identified on ¹⁸F-FDG PET-CT. SUV_max, glycolytic activity, and volume were determined for each tumor. Overall SUV_max, total tumor glycolytic activity (TGA), total metabolic tumor volume (MTV), and metabolic tumor burden (MTB) based on percentage of liver involvement (MTV/total liver volume) were calculated. Kaplan-Meier method, life-table analysis, and Cox proportional hazards model were used for statistical analysis.ResultsMedian SUV_max was 10.9 (range, 4.6–15.3), median TGA was 377.0 SUV/cm³ (range, 53.6–20,393.4 SUV/cm³), median MTV was 85.4 cm³ (range, 11.5–2,504.1 cm³), and median MTB was 5.5% (range, 0.1%–54.0%). MTB was found to be a significant negative prognostic marker of survival on univariate (P = .020) and multivariate (P = .018) analyses accounting for age and duration from metastatic diagnosis to first ⁹⁰Y treatment. A 60th percentile MTB of 7.0% (hazard ratio, 5.704; P = .040) was a statistically significant cutoff. Median survivals from first ⁹⁰Y treatment in patients with MTB < 7.0% and ≥ 7.0% were 10.8 months (95% confidence interval [CI], 6.8–14.8) and 4.7 months (95% CI, 1.6–7.8), respectively. SUV_max (P = .422), TGA (P = .064), and MTV (P = .065) were not found to be statistically significant.ConclusionsMTB based on ¹⁸F-FDG PET-CT performed before treatment was found to be a negative prognostic factor for patient survival after ⁹⁰Y radioembolization for unresectable metastatic melanoma to liver.     

Evaluation of Vascular Supply with Angio–Computed Tomography During Intra-Arterial Chemotherapy for Brain Tumors

We report the utility of a combined angiography and computed tomography (angio-CT) system in assessing drug distribution to the tumor during intra-arterial chemotherapy for metastatic brain tumors in a 65-year-old man. Although digital subtraction angiography did not clearly show tumor perfusion in two cerebellar tumors, angio-CT provided definite tumor perfusion in the complicated vascular territory, and anticancer agents were infused based on its findings. To our knowledge, however, this application for intra-arterial chemotherapy of brain tumors has not been previously described.     

Cone-Beam Computed Tomography–Guided Percutaneous Radiologic Gastrostomy

The purpose of this study was to investigate the feasibility of a flat-detector C-arm–guided radiographic technique (cone-beam computed tomography [CBCT]) for percutaneous radiologic gastrostomy (PRG) insertion. Eighteen patients (13 men and 5 women; mean age 62 years) in whom percutaneous endoscopic gastrostomy (PEG) had failed underwent CBCT-guided PRG insertion. PEG failure or unsuitability was caused by upper gastrointestinal tract obstruction in all cases. Indications for gastrostomy were esophageal and head and neck malignancies, respectively. Before the PRG procedure, initial C-arm CBCT scans were acquired. Three- and 2-dimensional soft-tissue reconstructions of the epigastrium region were generated on a dedicated workstation. Subsequently, gastropexy was performed with T-fasteners after CBCT-guided puncture of the stomach bubble, followed by insertion of an 14F balloon-retained catheter through a peel-away introducer. Puncture of the stomach bubble and PRG insertion was technically successful in all patients without alteration of the epigastric region. There was no malpositioning of the tube or other major periprocedural complications. In 2 patients, minor complications occurred during the first 30 days of follow-up (PRG malfunction: n = 1; slight infection: n = 1). Late complications, which were mainly tube disturbances, were observed in 2 patients. The mean follow-up time was 212 days. CBCT-guided PRG is a safe, well-tolerated, and successful method of gastrostomy insertion in patients in whom endoscopic gastrostomy is not feasible. CBCT provides detailed imaging of the soft tissue and surrounding structures of the epigastric region in one diagnostic tour and thus significantly improves the planning of PRG procedures.     

Multidetector Computed Tomography for the Assessment of Adnexal Mass: Is Unenhanced CT Scan Necessary?

Objective

To compare the diagnostic performance and radiation dose between contrast-enhanced CT (ECT) alone, and combined unenhanced and contrast-enhanced CT (UE + ECT) for the assessment of adnexal mass.

Materials and Methods

This retrospective study was approved by the Institutional Review Board. A total of 146 consecutive patients (mean age, 41.1 years) who underwent preoperative unenhanced and contrast-enhanced multidetector CT of the pelvis and had adnexal masses found at surgery were included. Two readers independently evaluated the likelihood of adnexal malignancy on a 5-point scale on two different imaging datasets (ECT alone and UE + ECT). The area under the receiver operating characteristic curve (AUC) was used to evaluate diagnostic performance. Radiation dose to patients was calculated by the volume CT dose index (CTDI_vol) and the dose length products (DLP) on each dataset.

Results

Of the total 178 adnexal masses, 133 masses were benign and 45 masses were malignant. For both readers, there is no significant difference of AUC values between ECT alone and UE + ECT for the detection of adnexal malignancy (reader 1, 0.93 vs. 0.95; reader 2, 0.92 vs. 0.91) (p > 0.05). The mean CTDI_vol (12.6 ± 2.2 mGy) and DLP (641.2 ± 137.2 mGy) of ECT alone was significantly lower than the mean CTDI_vol (21.5 ± 2.7 mGy) and DLP (923.6 ± 158.8 mGy) of UE + ECT (p < 0.0001).

Conclusion

The use of unenhanced CT scan in addition to contrast-enhanced CT scan does not improve the detection of adnexal malignancy, but increases radiation exposure.     

Comparison of General Anesthesia and Conscious Sedation During Computed Tomography–Guided Radiofrequency Ablation of T1a Renal Cell Carcinoma

Purpose

Percutaneous radiofrequency ablation is so painful that this treatment requires pain control such as conscious sedation or general anesthesia. It is still unclear which type of anesthesia is better for treatment outcomes of renal cell carcinoma. This study aimed to compare general anesthesia and conscious sedation in treating patients with renal cell carcinoma with radiofrequency ablation.

Percutaneous Computed Tomography–guided Renal Mass Radiofrequency Ablation versus Cryoablation: Doses of Sedation Medication Used

PurposeTo compare the amount of sedation medication administered during radiofrequency (RF) ablation versus cryoablation of small renal masses.Materials and MethodsRecords were retrospectively reviewed in patients who underwent percutaneous computed tomography–guided RF ablation and cryoablation of small renal masses from January 2002 to June 2011 for patient and tumor characteristics, amount of medications used for moderate sedation, and complications. Sedation was performed by giving patients titrated doses of midazolam and fentanyl. Additional medications were given if the desired level of sedation was not achieved.ResultsThere were 116 patients who underwent 136 ablation procedures; 71 patients underwent RF ablation, and 65 patients underwent cryoablation. RF ablation was associated with a significantly higher mean dose of fentanyl (mean dose for RF ablation, 236.43 μg; mean dose for cryoablation, 172.27 μg; P<.001). RF ablation was also associated with a higher mean dose of midazolam (mean dose for RF ablation, 4.5 mg; mean dose for cryoablation, 3.27 mg; P<.001). In the RF ablation group, two patients required additional sedation with droperidol. As a result of oversedation, two patients in the RF ablation cohort required sedation reversal with naloxone and flumazenil. None of the patients who underwent cryoablation required sedation reversal. No other sedation-related complications occurred.ConclusionsCryoablation of small renal masses was performed with less sedation medication than RF ablation. This finding suggests renal cryoablation is less painful than RF ablation; however, prospective studies with validated pain scales are needed to confirm these results.